Vitamin D Guidelines: What Is It, How Much Do You Need, & How to Get Enough

Ella Fitzgerald and Frank Sinatra agreed that “Life is sweet on the sunny side of the street.” Other singers have advised us to “Keep to the sunny side of life.” And The Beatles reminded us that “It’s all right,” because “Here comes the sun.”

We instinctively feel better on sunny days. And despite fears of melanoma, the fact is that being out in the sun, in moderation, is good for you. One of the coolest tricks your body can pull off is done by your skin, which converts sunlight into a hormone essential for human health. The hormone in question, known as calcitriol, is incorrectly referred to as vitamin D. Incorrectly because the definition of a vitamin is an essential nutrient that cannot be synthesized by the body in sufficient quantities to maintain health. With that bit of nitpicking out of the way, I’m going to conform to the prevailing norms, and call it vitamin D for the rest of this article.

Vitamin D, also known, for obvious reasons, as “the sunshine vitamin,” has a number of health benefits, most famously when it comes to your bone health. And it has come into the spotlight recently, in the context of COVID-19, as a potential immunity booster. (More about that later.)

But even though the evidence is clear that having enough vitamin D is critically important, 61% of the elderly population in the United States (and 96% in India) have some degree of vitamin D deficiency. Checking for vitamin D deficiency isn’t usually a part of standard blood tests in every physician’s office, so it’s often missed. And if you are deficient, you might not know it.

So what exactly is vitamin D? How much do you need? And do you need to supplement it?

What Is Vitamin D?

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 Vitamin D is called calcitriol, or sometimes cholecalciferol (vitamin D3), because it is calciferous (“carrying calcium around”) and a sterol (a type of steroid hormone).

Vitamin D is primarily obtained from your body’s response to the sun’s UV rays when they penetrate your skin. In addition to direct sun exposure, you can also get vitamin D from a few foods, as well as dietary supplements. It’s a fat-soluble vitamin, which means that if you take it orally, you’ll need to accompany it with at least some fat for the best absorption. Furthermore, while water-soluble vitamins are excreted and not stored in the body, vitamin D and other fat-soluble vitamins (like A, E, and K) accumulate in fatty tissues throughout your body.

Vitamin D promotes calcium absorption in your gut and helps your body to maintain adequate serum calcium and phosphate concentrations. Vitamin D also works together with vitamin K to regulate calcium metabolism, which is essential for heart health. And it also plays a key role in skeletal health and bone strength. Plus, it controls the reduction of inflammation, as well as modulation of processes like cell growth, neuromuscular and immune function, and glucose metabolism.

6 Health Benefits of Optimal Vitamin D

Your body needs vitamin D — and enough of it — to run properly. In fact, vitamin D offers a number of health benefits both on its own and through working together with other compounds in the body. Here are six great reasons to “Let the sunshine in” on a regular basis.

1. It’s good for your muscles and bones.

You need vitamin D in order to absorb calcium, which is necessary to grow and maintain strong bones. Research shows that when people are vitamin D deficient, they have worsened skeletal integrity. For example, in a 2017 study published in Nutrients, researchers found that supplementation of vitamin D2 over the course of six months reduced oxidative protein damage, decreased self-reported pain, improved quality of life, and improved grip strength and physical performance in osteoarthritis patients. Let’s recap: less damage, less pain, stronger, and happier. Sounds good to me!

In addition to bone health, vitamin D is also needed for the normal development and growth of muscle fibers — the thousands of muscle cells that are tightly wrapped together to form your muscles. As such, having inadequate levels of vitamin D in the body can lead to muscle weakness and pain.

2. It might have protective effects against cancer.

Research has shown that having higher serum levels of vitamin D is associated with a lower cancer incidence. In fact, a 2019 meta-analysis of prospective cohort studies published in Nutrients looked at 16 studies involving 101,794 participants to determine the relationship between serum vitamin D levels and risk of cancer diagnosis and mortality. The researchers concluded that with each 20 nmol/L (that’s pronounced “nanomoles per liter,” in case you’re reading this article out loud as a bedtime story) increment increase of 25-hydroxyvitamin D (another name for calcidiol) concentration, the risk of developing cancer dropped by seven percent.

This relationship remains when looking at specific types of cancer, too. Another 2019 study found that higher serum vitamin D levels were associated with statistically significant, substantially lower risk of colorectal cancer among women. While not as significant, the same association was also seen among men. And in a 2020 review, researchers concluded that epidemiological evidence suggests there is a link between higher vitamin D levels and a lower risk for ovarian cancer as well.

3. It offers cardiovascular benefits.

Another health benefit of having adequate vitamin D levels in your body is heart health protection. A 2017 meta-analysis of 32 studies published in the American Journal of Clinical Nutrition found that higher serum vitamin D levels were inversely associated with total cardiovascular disease events, like heart attacks and strokes, and, ultimately, mortality from them.

A 2018 review and meta-analysis published in Nutrients also examined the relationship between vitamin D levels and ischemic stroke risk. The authors found that having lower vitamin D status was associated with a higher risk for ischemic stroke.

4. It may be protective against autoimmune diseases.

An autoimmune disease is a condition in which your immune system mistakenly attacks your body. A 2017 study published in Neurology found that vitamin D deficiency is a risk factor for multiple sclerosis, a physically and mentally progressive autoimmune disease in which the insulating covers of nerve cells in the brain and spinal cord are damaged. In a broader review from 2018, researchers concluded that vitamin D deficiency is prevalent in a number of autoimmune diseases. As such, vitamin D supplementation has been linked to the prevention of autoimmune diseases.

5. It may help prevent and manage type 2 diabetes.

Having adequate vitamin D levels appears to be helpful in the management of type 2 diabetes as well. In a 2018 review published in Nutrients, researchers found that when serum vitamin D levels among people with type 2 diabetes were increased, their insulin resistance was reduced.

In another 2018 meta-analysis, researchers found that low vitamin D levels were associated with an increased risk for hyperglycemia — or uncontrolled high blood sugar — in both people who did and did not have diabetes.

6. It may protect your body against viral infections.

Vitamin D has recently been highlighted as a key player in the strength of our immune systems, especially when it comes to fighting off viral infections. 

In a 2020 study, researchers examined the mean vitamin D levels among populations from 20 European countries as well as the documented cases of COVID-19 and the subsequent mortality rates from the virus. They found a potential correlation between lower vitamin D levels and higher incidence of COVID-19 risk and mortality. 

An additional Spanish study on COVID-19 outcomes used vitamin D to treat patients already hospitalized for the disease. A total of 76 patients in the study were given the immunosuppressant hydroxychloroquine and the antibiotic azithromycin. Fifty of them were also given oral calcifediol (a vitamin D3 analog) daily, while 26 were not.

Of the 50 patients treated with calcifediol, only one required admission to the ICU (2%), while of 26 untreated patients, 13 required ICU admission (50%), and two died (8%). Although this was a small sampling of participants, the results were statistically significant when it came to reducing the severity of the disease.

These studies suggest that both screening for vitamin D deficiency and possibly using it as a supplementary treatment could play an important role in pandemic-related public health. 

Other studies tell us that addressing vitamin D deficiency could also help protect against other viral illnesses, like seasonal influenza. 

Vitamin D Deficiency

Vitamin D deficiency — or not having enough vitamin D circulating in your blood — is a very common condition. Subclinical vitamin D deficiency is widely prevalent in almost every nation, impacting up to a billion people worldwide.

With chronic and/or severe vitamin D deficiency, a decline in intestinal absorption of calcium and phosphorus leads to hypocalcemia or a deficiency of calcium in the blood. Inadequate calcium can lead to secondary hyperparathyroidism, a condition in which your parathyroid glands make too much parathyroid hormone. This can result in accelerated bone demineralization, which can eventually turn into osteomalacia (softened bones) and osteoporosis (porous bones) in adults as well as rickets (softened and weakened bones) in children. Whew — a lot of hard words there. If you’re still reading this, you deserve a medal!

Vitamin D deficiency is diagnosed when the amount of vitamin D circulating in your bloodstream is lower than recommended levels for optimal health. So what should your levels be? That’s where the controversy begins! And it turns out there are many credible researchers coming to very different conclusions.

Guidelines for Vitamin D Levels

In 2011, the widely respected Endocrine Society issued a report which concluded: “Based on all the evidence, at a minimum, we recommend vitamin D levels of 30 ng/mL, and because of the vagaries of some of the assays, to guarantee sufficiency, we recommend between 40 and 60 ng/mL for both children and adults.” (That one is pronounced “nanograms per milliliter.”)

However, writing for the New England Journal of Medicine in 2016, several leading epidemiologists and endocrinologists stated that in their opinion, we are over-screening for vitamin D deficiency and unnecessarily treating individuals who are actually fine. Based on their analysis, a more appropriate cutoff for vitamin D deficiency would be much lower — 12.5 ng/mL.

This leads to another question, which is maybe what we should have been asking all along. What is optimal? Apparently, most people can survive with blood levels as low as 12.5 ng/mL. But is that what’s best?

Here too, there is controversy. But a growing body of research is finding that the optimal blood levels of vitamin D are above 30 ng/mL, while other studies conclude that 40-60 ng/mL is the preferred range. 

Can You Get Too Much Vitamin D?

The short answer is, yes. Remember that vitamin D is a fat-soluble vitamin, which means that it accumulates in your body and is stored over time — unlike water-soluble vitamins that are just peed away if you consume more than you need. So vitamin D can build up in your body, and side effects and toxicity are possible if your blood levels get too high.

Vitamin D helps your body absorb calcium from the food you eat. But too much of it can cause your body to store up excess calcium in your blood. Symptoms of hypercalcemia, or high blood calcium levels, include digestive distress, fatigue, and bone loss. And a 2019 study concluded that excessive use of vitamin D could cause kidney damage in people who are not deficient in the vitamin.

It’s important to clarify that excess vitamin D levels result from oral intake only; you can’t overdose on the vitamin D your body makes from sunlight. Your body is remarkably good at regulating how much naturally produced vitamin D is made and stored.

Vitamin D Toxicity?

Blood levels of 100 ng/mL are considered to be the upper limit of a normal or healthy range by the Institute of Medicine, the Endocrine Society, and many reference laboratories. But it turns out, it’s not easy to get your vitamin D levels that high. In one major study involving more than 17,000 healthy adult volunteers, vitamin D supplements as high as 20,000 international units (IU) per day didn’t get participant’s blood levels above 100 ng/mL and also didn’t lead to any evident toxic effects.

A 2015 study looked at data from more than 20,000 people over the course of 10 years. The researchers found that only 37 people had levels above 100 ng/ml.

However, while 100 ng/mL might be a rarely reached upper limit, there are studies that have shown a small level of increased mortality with blood levels of 50 ng/mL or higher. While the evidence is a bit murky, it does seem that vitamin D toxicity is rare, and that somewhere in the 30-60 ng/mL range could be the “sweet spot” for most people.

Getting Your Levels Checked

There are certain individual factors that can increase your risk of being vitamin D deficient. Some of these include:

• Not eating fatty fish (since they are the main source of dietary vitamin D);
• Being of advanced age;
• Having limited or inconsistent outdoor sun exposure;
• Having high melanin levels in your skin (generally, this accompanies dark skin pigmentation);
• Having medical conditions that can limit fat absorption;
• And being obese.

If you fall into any of these categories, checking your vitamin D levels is especially important.

Getting your vitamin D blood levels checked isn’t difficult. The test can be done with a pinprick of blood. This could give you very useful information. If you decide to take a significant dose of supplemental vitamin D (over 2,000 IUs per day), you may want to check your blood levels again after a few months of doing so to see if or how things have changed.

Studies have shown that each additional 100 IU of vitamin D3 you consume per day will raise your blood vitamin D levels by 1 ng/ml (2.5 nmol/l), on average. 

There are also options to check your vitamin D at home, using a finger prick test. These can be easily obtained and done without a doctor’s prescription, such as the EverlyWell Vitamin D Test. Simply conduct the test in the comfort of your own home (which you will temporarily make marginally less comfortable by drawing blood from your fingertip), and ship it using the prepaid shipping label, where it will be evaluated in a test lab by a physician. Your results will be uploaded to a secure online platform within one to two weeks of receipt.

Where Can You Get Vitamin D?

Sunshine

When your skin is exposed to sunlight, it manufactures vitamin D. The sun’s ultraviolet B (UVB) rays interact with a protein called 7-DHC in your skin, converting it into vitamin D3 — the active form of vitamin D. This is the best way to get vitamin D. Recommendations for time in the sun vary and depend on individual factors like skin pigmentation, age, the latitude of where you live (there is less direct sunlight further from the equator), skin cancer risk, and the season. But you don’t need to devote hours a day to sun-worship; recommendations range from 7-30 minutes per day over a large portion of your body. Studies have found that people with dark skin pigmentation may need up to sixfold more sun exposure than people with light skin to get the same vitamin D3 production in their skin.

Food

While there are some dietary sources of vitamin D, very few foods naturally contain it. Vitamin D is found in certain types of fatty fish (e.g., halibut, salmon, and mackerel), animal organ meats like liver, and in very small amounts in eggs and dairy products. Most foods containing vitamin D, including dairy milk, are fortified with it, meaning that the nutrient is added to them as a supplement. You can find vitamin D in fortified cereals, orange juice, and many plant-based milks, and it will be noted on the ingredients list.

The only plant-based foods that naturally contain vitamin D are some types of mushrooms, which contain it in the form of vitamin D2. Mushrooms produce vitamin D similarly to how humans do when our skin is exposed to sunlight. The vitamin D content of mushrooms can be increased either by exposing them to direct sunlight or using UV lamps during their growing process.

Supplements

The most reliable way to raise your vitamin D levels is to take it as a supplement. There are two main forms of vitamin D: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). These two types of vitamin D are not equal when it comes to raising your serum vitamin D status. Both are effectively absorbed into the bloodstream, but your liver metabolizes them differently. Vitamin D3 appears to be much more effective in raising blood vitamin D levels than vitamin D2.

Vitamin D Supplements

Vitamin D can be found as a supplement on its own or as part of a multivitamin. It’s also added to a number of omega-3 fatty acid supplements.

Note that the American Academy of Pediatrics recommends all breastfed babies receive a daily dosage of 400 IU of vitamin D soon after birth to maintain their levels. This is because vitamin D is not transferred well through breastmilk. And babies generally shouldn’t be exposed to much sunlight. Formula-fed babies don’t typically need this supplementation because infant formula is fortified with the vitamin D they need.

Most supplements come in the form of vitamin D3, or cholecalciferol. However, most D3 supplements are not manufactured from vegan sources. Instead, many come from animal products such as lanolin, which is a greasy substance produced by sebaceous glands of sheep and found in their wool. Still, vegan vitamin D3 supplements are becoming increasingly widespread. These are usually made from lichen, an organism that arises from algae or cyanobacteria. Vegan vitamin D2 supplements are also available but not usually recommended because they’re not as reliable when it comes to raising serum vitamin D levels. Plus, vitamin D2 appears to be more prone to degradation over time.

Micellized Vitamin D

While many vitamin D supplements come in gel, oil, or capsule form, there are also liquid dropper options called micellized vitamin D3. Micellization of vitamin D3 appears to improve its solubility, absorption, and bioavailability. Which explains why a miscible form of vitamin D3 may actually be more effective in raising serum vitamin D levels than a fat-soluble version.

(I tried to understand what micellization means, but when the first definition I found online stated, “Micellization is a dynamic phenomenon in which n monomeric surfactant molecules S associate to form a micelle Sn,” I decided that I didn’t need to know that badly.)

A 2016 study published in the Journal of Pediatric Endocrinology and Metabolism examined the effects of either 60,000 IU of fat-soluble vitamin D3 per month with milk or 60,000 IU per month of water-miscible vitamin D3. The study lasted for six months, and included 180 healthy kids, ages 13-14 years old. They found that the miscible form resulted in a significantly greater increase of serum vitamin D levels among the study participants.

Vitamin D and Vitamin K2

Research also indicates that vitamin D3 is best absorbed when paired with the nutrient vitamin K2. High blood levels of vitamin D — a potential problem for anyone taking D3 supplementation — can lead to excessive calcium accumulation in the blood, contributing to calcification of the blood vessels. Vitamin K2 helps make sure that calcium is used in the bones instead of ending up in the arteries where it doesn’t belong.

Once the vitamin D has done the job of making sure the calcium you consume hits your bloodstream, the vitamin K activates a protein called osteocalcin. This protein makes sure that the calcium that’s in your bloodstream winds up where you want it to go — in your bones and teeth.

Bottom line: You don’t want to be deficient in vitamin K if you’re taking vitamin D. For this reason, many people take their vitamin D and K together.

Get Your Sunshine Vitamin

Vitamin D is an essential fat-soluble vitamin that has a number of health benefits, including contributing to optimal bone health and a strong immune defense. Your skin makes it in response to sun exposure. And there are a relatively small amount of foods that have it. However, a billion people may still be deficient in it. And unless you spend lots of time in the sunshine, you may be as well, so supplementation is often recommended. But because it’s possible to get too much vitamin D, a blood test is also advisable to help you ensure you are in a healthy range.

As in all things: Use your own best judgment. And where appropriate, consult with a qualified healthcare professional about your specific health needs.

Fonte: Food Revolution Network

As informações e sugestões contidas neste blog são meramente informativas e não devem substituir consultas com médicos especialistas.

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Vitamin K: Benefits, How to Get It, and How Much You Need

In 1916, a chemist named Cornelia Kennedy left her job teaching “domestic science” to female students at the University of Minnesota for a research position at the University of Wisconsin, where her advisor was trying to figure out how to put together healthy animal feeds. In a paper on malnourished pigeons, Kennedy wrote of two chemicals, which she called “fat-soluble A and water-soluble B.” And just like that, we had a naming system for these newly-discovered nutrients, which came to be known as vitamins.

You’re undoubtedly familiar with the first five vitamins to be identified and named: A, B, C, D, and E. But then what happened? The next (and as it turned out, final) alphabetic vitamin is K, seemingly an insignificant afterthought. What happened to F, G, H, I, and J? Did scientists not know the alphabet song? Is vitamin K really not a big deal? This article covers what vitamin K is and does, how much you need, and the best places to get it in your diet.

What Is Vitamin K?

 

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Vitamin K is a fat-soluble vitamin, which means it doesn’t dissolve in water. And excess (unused) amounts in your body are stored in your liver and fatty tissues. The absorption of vitamin K and other fat-soluble vitamins is best optimized when you consume them with some dietary fat.

Vitamin K is primarily involved in blood clotting, bone metabolism, and building proteins. It does its work in your liver and other tissues, including your brain, pancreas, and heart, as well as your skeletal system. Discovered in 1929, it was named vitamin K not as part of the alphabet scheme, but because the Danish researcher Henrik Dam found that it prevented chickens on a fat-free diet from bleeding out. He called it the “koagulation” vitamin (using the German spelling), or vitamin K.

And why not vitamin F, the next letter in line? It turns out that F, G, and H had been used until the chemical compounds they referred to were found not to be actual vitamins: F turned out to be the omega fatty acids; G was discovered to be part of the B vitamin group (B2, to be exact), and H was reclassified as biotin (or B7). So by the time Henrik Dam cured chicken bleed-out with hemp seeds, he was free to choose any letter he wanted.

Back to our story. Unlike the other fat-soluble vitamins, only very small amounts of vitamin K circulate in your blood at any given time. In fact, if you take a one-time, supplemental dose of vitamin K, your body will keep approximately 30-40% of it to use and store, and get rid of the rest. Your body has a limited amount of storage for vitamin K, so some of it is also recycled and reused multiple times.

Types of Vitamin K

While vitamin K sounds like one compound, there are actually two kinds. The first is vitamin K1, or phylloquinone, which is primarily found in cauliflower and leafy green veggies like spinach, kale, and cabbage. This is the main form of vitamin K found in the diet, yet some studies show most people absorb only about 10% of the vitamin K1 they ingest.

The other type is vitamin K2, or menaquinone, which is predominantly made by human and animal gut bacteria. Moderate amounts of K2 are found in certain fermented soy foods (especially natto, which is something of an acquired taste) and animal products like butter, beef liver, curdled cheese, and egg yolks. Interestingly, your gut bacteria appear to convert some vitamin K1 from your diet into K2, although the extent and efficiency of this conversion varies based on a number of factors.

Vitamin K Health Benefits

Both vitamin K1 and K2 are important for maintaining your overall health. Below are a few of the best-known health benefits of both forms of vitamin K.

Helps with Blood Coagulation

This may be the most well-known role of vitamin K in your body. Remember, vitamin K was named after the German word “koagulation.” Both vitamins K1 and K2 are involved in blood clotting, which is what keeps you from bleeding to death when you get a cut. Specifically, vitamin K is needed to manage proteins involved in the blood clotting process. If you don’t get enough vitamin K, you are more likely to experience hemorrhaging, or excessive bleeding, from a wound.

Good for Your Teeth and Bones

Inadequate intake of vitamin K has been linked to an increased risk for osteoporosis — a disease in which the bones become soft and porous — and bone fractures. Both vitamins K1 and K2 may also help with regulating calcium balance, which maintains skeletal strength. Seven trials have found that vitamin K2, specifically, reduced spinal fractures by 60%, hip fractures by 77%, and all non-spinal fractures by 81%. High doses of vitamin K2 have also been used to prevent further bone mineral loss and reduce the risk of fractures in patients with osteoporosis.

Vitamin K2-Specific Health Benefits

There are also some health benefits that seem to be tied only to vitamin K2.

May Reduce Your Risk of Heart Disease

Vitamin K2 may help prevent calcification that results from calcium buildup in your arteries. This accumulation is associated with atherosclerosis, a risk factor for heart disease. A 2009 study of 16,057 women found that for every 10 mcg of K2 that participants consumed each day, their heart disease risk was reduced by 9%.

May Support Brain Health

Vitamin K2 seems to be involved in processes that help protect your brain as you age. For instance, it plays a role in the production of compounds called sphingolipids, which are highly concentrated in the brain (and which sound like a lot of fun!). Changes in the metabolism of sphingolipids have been linked to neurodegenerative diseases like Alzheimer’s. Recent evidence also suggests that vitamin K2 may help protect against oxidative stress and inflammation, and may influence psychomotor behavior and brain function.

May Have Anticancer Benefits

A few studies have indicated that vitamin K2 may help reduce the recurrence of liver cancer and increase survival. And in a 2008 study published in the American Journal of Clinical Nutrition, researchers found that men with a high intake of vitamin K2 had a 63% lower risk for advanced prostate cancer.

How Much Vitamin K Do You Need?

Vitamin K is obviously doing some important work in your body, so how much should you be getting? Currently, most health authorities focus on K1 specifically, which is a shame because it seems that K2 is equally important for long-term health. According to the National Academy of Medicine, the daily requirement for vitamin K1 from foods is 90 micrograms (mcg) for women and 120 mcg for men. The World Health Organization and the Food and Agriculture Organization make recommendations that come out to an average of 55 mcg per day for women and 65 mcg per day for men.

While the recommended amounts vary, for most people getting enough vitamin K1 is not a problem. Most people who eat enough total calories get more than the recommended amount of it.

But K2 seems like it deserves more attention. And a few health authorities have even gone so far as to state a separate recommendation for it. Some scientists studying the effects of K2 suggest that its health benefits are best seen with a daily intake of between 10-40 mcg. 

Vitamin K Deficiency

While deficiency of vitamin K1 is rare, it’s possible in the event of severe malnutrition. Those suffering from gastrointestinal disorders, or who have trouble absorbing fat, may be at risk of K1 deficiency. Other at-risk groups include babies who are breastfed by mothers who are vitamin K deficient, and adults who have taken coumarin anticoagulants (the best-known are the blood-thinning medications Coumadin and Warfarin). This is because these drugs can interfere with the synthesis of vitamin-K dependent coagulation proteins in the liver. Members of these groups may need their vitamin K status monitored. And they may require supplementation but should discuss the matter with a qualified healthcare provider first.

Vitamin K2 deficiency is trickier to diagnose, as the harm is mostly long-term. However, problems with blood clotting — like excessive bleeding from wounds — or unexplainable bruising under the skin may be signs of a potential K2 deficiency and should be examined further.

There may also be a link between vitamin K deficiency and osteoporosis. Studies have found that vitamin K2 prevents osteoporotic fractures and prevents vertebral fractures.

Vitamin K-Rich Foods

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Some of the best vitamin K1-containing foods are:

• Leafy greens, such as spinach, mustard greens, and collard greens
• Cruciferous vegetables, such as Brussels sprouts, kale, broccoli, and cauliflower
• Asparagus
• Prunes
• Peas
• Parsley
• Scallions

And some of the most vitamin K2-rich foods are:

• Natto, which is by far the highest plant-based source of vitamin K2
• Tempeh
• Sauerkraut
• Kimchi
• Fermented pickles
• Animal products, like butter, egg yolks, organ meats, and high-fat dairy (more so if they are grass-fed or pasture-raised)

Note that while certain animal products are high sources of vitamin K2, they come with other health problems. Many are linked to a higher risk for obesity and chronic diseases like cancer, heart disease, type 2 diabetes, and neurodegenerative diseases like dementia. If you don’t want to go that route, you may want to include natto in your diet, and/or consider a supplement.

In case you’re not familiar with natto, it’s a Japanese dish, traditionally served for breakfast, consisting of soybeans fermented with natto bacillus. According to many Westerners, it’s an acquired taste. Some natto fans claim it tastes a bit like ripe brie cheese, and may even have overtones of bacon. You can find natto at specialty food stores and online, or you can be adventurous and make your own. A single teaspoon provides 50 mcg of vitamin K2. There is also some vitamin K2 in sauerkraut, tempeh, and other fermented foods, though amounts vary so it’s hard to know how much you’re getting.

3 Vitamin K-Rich Recipes

You’ll see in the recipes below that getting vitamin K1 and K2 on a plant-based diet can be delicious. Easy-to-prepare, tasty dishes like Spinach Artichoke Dip, Tempeh Italiano Farro and Spinach, and Cauliflower Steak with Peanut Sauce provide nutrients your body needs and loves to support heart, bone, and cognitive health.

1. Spinach Artichoke Dip

You can get an abundance of vitamin K1 in this tasty appetizer or snack. If you’re looking for a creamy, savory, and tasty treat that delivers a bundle of nutrients —  then try out this mouth-watering Spinach Artichoke Dip!

2. Tempeh Italiano Farro and Spinach

You’ll find both vitamins K1 and K2 in this nutrient-dense grain bowl. Also, farro is packed with fiber (five grams in just ¼ cup of the dry grain!), which helps to cultivate diverse, healthy bacteria in your gut. Not to mention, this delicious dish is sure to please the entire family!

3. Cauliflower Steak with Peanut Sauce

Cauliflower steaks provide satisfying texture and flavor while delivering so many essential nutrients, including vitamin K1 that the body needs to function properly and at its best. It also offers phytonutrients and fiber — both of which help to foster a healthy gut and the conversion of K1 into K2. And unless you’re allergic, don’t skip the peanut sauce! The healthy fat in the peanuts will help with the absorption of vitamin K (see the Chef’s Notes for peanut- and nut-free options). Bonus: Add a spoonful of kimchi or kraut on top for some dietary vitamin K2.

Vitamin K Testing

Testing for vitamin K1 deficiency is not typically done routinely, except in the case of severe bleeding or hemorrhaging, which can be a symptom of severe deficiency. The primary lab test performed to evaluate for vitamin K1 deficiency is called prothrombin time (PT). This measures the time it takes for your body to form blood clots and stop active bleeding. If the result of the PT test is prolonged — meaning that blood clotting takes longer than it should — and is suspected to be a result of low vitamin K1, then vitamin K1 supplementation is typically prescribed.

While tests for Vitamin K1 are aimed at blood clotting and coagulation, tests aimed at K2 are focused on bone health markers. Testing for Vitamin K2 is more difficult because Vitamin K2 itself is challenging to measure. But labs can measure levels of osteocalcin, which is a protein found in bones and teeth that is activated by Vitamin K2. If you can measure the level of activation of this Vitamin K2-dependent protein, you get a rough idea of your Vitamin K2 status.

In the US, both LabCorp and Quest Diagnostics offer Osteocalcin tests.

Should You Take a Vitamin K Supplement?

Vitamin K1 is found widely in foods. If you are eating enough food — and especially if your diet includes a decent amount of leafy vegetables — you will almost certainly get more than you need. But vitamin K2 is a bit more tricky. Some people are able to convert vitamin K1 to vitamin K2. But not everyone has the ability to. And since the main sources of vitamin K2 in the modern diet are certain fermented soy products, and animal products (specifically high-fat dairy products from grass-fed cows, egg yolks, and organ meats), many people, and especially vegans, may want to consider a supplement. 

A word of caution: People who are taking anticoagulant medications need to consciously maintain a consistent and specific intake of vitamin K from food and supplements. Sudden changes in how much vitamin K they’re getting can impact the anticoagulant effect of their medication, either amplifying or reducing its activity.

Vitamin K2 and Vitamin D

Vitamin D, another fat-soluble vitamin, works closely with vitamin K to perform various bodily functions, like regulating calcium metabolism for bone and heart health.

Research has also shown that Vitamin K2 also appears to boost the absorption of vitamin D. While having high circulating levels of vitamin D can result in excessive calcium buildup in your blood, vitamin K2 helps make sure the calcium is used for your bones instead of ending up in your arteries and causing potential heart health issues.

How does this happen? After vitamin D helps transport calcium into your blood, vitamin K2 activates osteocalcin, a protein that moves the calcium from your blood to your bones and teeth.

This beautiful partnership between vitamin D and K2 runs most efficiently by making sure you’re not deficient in either critical vitamin. It’s for this reason that many people take their vitamin D and K supplements at the same time.

Get Your Coagulation Vitamin

Vitamin K is an essential fat-soluble vitamin that comes in two forms, vitamin K1 and K2. K1 primarily has benefits for blood clotting, while K2 has additional benefits for bone, heart, and brain health, as well as potential cancer prevention. Although the recommended daily intake for vitamin K is only based on vitamin K1, K2 supplementation may be recommended to avoid deficiency, especially for plant-based eaters, since its plant-based sources are limited.

Fonte: Food Revolution Network

As informações e sugestões contidas neste blog são meramente informativas e não devem substituir consultas com médicos especialistas.

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Vitamin B12: Why it’s Important and How to Avoid B12 Deficiency

Picture a no-holds-barred diet debate. The topic: “Is a vegan diet healthy for humans?” The anti-vegan debater utters two syllables and drops the mic, confident of victory. What are those syllables? “B” and “12.”

Here’s the deal: B12 is an essential vitamin, crucial for many bodily functions. And many people can’t get enough B12 from an exclusively plant-based diet without some form of supplementation. Therefore, the anti-vegan concludes, plant-based diets are unnatural and unhealthy. Case closed, and let’s break out the ribeyes.

Well, not so fast. While it’s true that B12 is an essential nutrient, and it’s hard to get enough from plants, there’s a lot more to the story. Many non-vegans are also low on B12, for a variety of reasons having to do with individual health issues, as well as modern agricultural and sanitation practices. And many people actually host bacteria that make B12 in their digestive tracts.

No matter what your diet, this article tells you what you need to know about B12. You’ll find out what it is, where it comes from, why it’s so important for your health, how much you need, and where to find the healthiest sources.

What Is Vitamin B12?

 

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Of all the known vitamins, vitamin B12 is the largest and has the most complex structure. (Think of it as the vitamin equivalent of book five of the Harry Potter series.) Like all the other B vitamins, B12 is water-soluble. This means that your body uses what it needs and excretes the rest through your urine. While some people can store vitamin B12 in their bodies for a long time (up to four years), it’s important to get a regular supply in order to prevent deficiency.

Vitamin B12 contains the metallic chemical element cobalt, which is why B12 compounds are also known as cobalamins. (It turns out that Wolverine isn’t the only one with a partly metallic body!) Your body requires B12 to form red blood cells, to keep your brain functioning well, and to synthesize DNA. B12 also plays an essential role in folate (vitamin B9) metabolism, which is a critical nutrient for reproduction. In other words, no B12, no life.

B12 Benefits for Your Health

Vitamin B12 is critically important for a lot of reasons. It contributes to a vast array of processes that keep your body running smoothly and that support your overall health. Here are just a few crucial benefits of B12.

1. Helps fight depression.

Getting enough vitamin B12 supports brain health and positive mood. Observational studies have found that approximately one-third of patients who are admitted for clinical treatment of depression are deficient in vitamin B12.

2. Protects against cardiovascular disease.

Vitamin B12 helps regulate levels of homocysteine, a byproduct of protein metabolism. High levels of homocysteine have been linked to a higher risk of heart disease, stroke, and dementia. Homocysteine levels increase when B12 is deficient and decrease when there is enough B12 in the body. (Think of B12 and homocysteine on opposite sides of a see-saw.) Many studies conducted between 1999-2003 found that vegans who were not supplementing with vitamin B12 had unusually high levels of homocysteine, whereas those who did supplement had homocysteine levels that fell within a normal range.

3. Protects against eye disease and disorders.

Vitamin B12’s ability to bring down homocysteine levels benefits not only your cardiovascular system and your brain but your eyes as well. Elevated homocysteine levels appear to increase the risk of a number of eye-related diseases, including (warning: list of medical jargon coming up) retinopathy, cataracts, optic atrophy, retinal vessel atherosclerosis, and pseudoexfoliative glaucoma maculopathy (I don’t recommend trying to say this five times fast).

And that’s not all. Age-related macular degeneration is associated with both high homocysteine levels and low levels of vitamin B12. The good news is that vitamin B12 and folate supplementation can be helpful in helping elderly people reduce the high homocysteine levels that can lead to eye disease. And remarkably, the topical application of vitamin B12 along with citicoline — a naturally-occurring brain chemical sometimes used in supplements — to the eyes of patients suffering from diabetic retinopathy actually regrew damaged nerves, improving their corneal nerve health. Now that’s some real-life magic right there!

4. Protects against neural tube defects in pregnancy.

Neural tube defects are serious birth defects that can change the function or shape of the spinal cord and brain. While we most often hear about the importance of folate for preventing neural tube defects, vitamin B12 also plays a crucial role. Fetuses of mothers with low levels of vitamin B12 are at a higher risk for neural tube defects, including spina bifida and anencephaly, among others.

5. Helps with red blood cell formation.

Vitamin B12 also helps to make sure you have enough red blood cells in circulation. In turn, it supports oxygen availability in your body and may improve athletic performance. A 2020 study published in the journal Nutrients examined 1,131 blood samples collected from 243 track and field athletes over six years and compared the results to athletic performance. The researchers concluded that the ideal athletic performance was achieved when blood levels of B12 were in the range of 400-700 pg/mL (that’s picograms per milliliter. And in case you’ve never heard of a picogram before, it’s one trillionth of a gram).

6. Has a protective effect on DNA.

Vitamin B12 has antioxidant properties, which is one of the reasons it can both protect your cells from damage caused by free radicals and reduce your cancer risk. If Jeff Goldblum had gotten enough B12, I suspect The Fly would have been a very different (and much less scary) movie.

Having enough vitamin B12 in your system can also help protect you against the toxicity of some drugs. One 2014 study, for example, found that vitamin B12 was protective against the known free radical damage caused by Paclitaxel, an anticancer drug that leads to irreversible cell injury. And a 2018 study found that vitamin B12 reduced toxicity from hydrochlorothiazide, a diuretic drug used to treat high blood pressure and fluid-related swelling.

Where Does Vitamin B12 Come From?

There are many misconceptions about B12, but the truth is that this critical vitamin does not actually come from meat. Rather, B12 is made only by bacteria and single-celled organisms. And where, pray tell, are these B12 producing microorganisms found? In soil, and in the small intestine of animals, including humans.

Before the advent of modern sterilization practices, you could get B12 pretty much everywhere, including by eating vegetables that had a teeny bit of dirt left on them. Or by drinking well or river water, or just by working in a garden.

These days, though, most of us drink chlorinated water, which kills the B12-producing bacteria (as well, of course, as the nasty pathogens that cause cholera, typhoid, and dysentery). Furthermore, much of our farmland today is sterile since it’s fed with synthetic fertilizers instead of decaying plant and animal matter in which B12 bacteria can survive.

Meanwhile, our society has developed a collective fear of dirt and germs. While there are undeniable public health benefits to our anti-microbial efforts, there are serious negative side effects as well, including a lack of bioavailable B12 in our environment.

And remember our anti-vegan debater crowing about the fact that vegans have to supplement with B12, and how it “proves” that their diet is inherently unhealthy and unnatural? Well, the sad truth is that factory-farmed animals are also B12 deficient, so they receive supplementation in their feed. This means that no matter where you’re getting your B12, it’s likely to depend at least in part on supplementation. The real question is whether you supplement directly or take it through a middleman, er, middle-cow or middle-chicken.

How Much Vitamin B12 Do You Need?

It’s not just a matter of how much B12 you take in; it’s also how much you can use. The vitamin must be bioavailable. And you must be able to absorb and transport it efficiently as well. For instance, optimal B12 absorption can only be achieved when there’s enough intrinsic factor — a transporter protein for B12 — in the digestive system.

And with all of the factors in our world today that can throw off our gut microbiome, it’s not just vegans or vegetarians who are at risk for B12 deficiency. In fact, according to one study of 3,000 people conducted a while back by researchers at Tufts University, up to 39% of the US population could have low B12 levels. That’s why it’s crucial to understand how to get vitamin B12 from dietary and/or supplemental sources, and how much you need in order to maintain optimal levels.

Below are the recommended daily needs for vitamin B12, based on established Adequate Intake and Recommended Dietary Allowances:

• 0-6 months: 0.4 mcg (micrograms, or millionths of a gram)
• 7-12 months: 0.5 mcg
• 1-3 years: 0.9 mg
• 4-8 years: 1.2 mcg
• 9-13 years: 1.8 mcg
• 14+ years: 2.4 mcg
• Pregnancy: 2.6 mcg
• Lactation: 2.8 mcg

As you can see, the recommended intake varies depending on age, pregnancy status, and diet. But minimum daily needs data can be misleading. The truth is that if your absorption is suboptimal for any reason, which is increasingly the case as you grow older, your actual needs might be higher.

B12 Deficiency

If you don’t get enough vitamin B12, either because of inadequate intake, poor absorption, and/or inability to make your own in tandem with the bacteria in your gut, you’re at risk of a B12 deficiency.

What are some of the more common symptoms of B12 deficiency? They can include fatigue, weakness, constipation, loss of appetite, weight loss, tingling of hands and feet, sore mouth or tongue, difficulty balancing, confusion, and poor memory. In infants, it can look like failure to thrive, movement disorders, and developmental delays.

Of course, the best way to know how efficient your body is at producing — and absorbing — vitamin B12 is to have your blood levels tested. A vitamin B12 test can be done at the same time as other general labs at a wellness check-up. But because it’s not a standard test, you will have to request it in most cases. It typically costs $30-50 for such a test.

In western medicine today, B12 deficiency is generally suspected when blood levels of B12 fall below 200 pg/mL. But research suggests that levels of at least 400 pg/mL are closer to optimal.

Who Is Most At Risk for Vitamin B12 Deficiency?

While vitamin B12 deficiency can affect anyone, certain groups are at higher risk.

The most common cause of B12 deficiency is poor absorption, which can result from conditions like irritable bowel disease, Celiac disease, AIDS, or bacterial overgrowth in the small intestine. The elderly population is also at heightened risk because B12 absorption worsens with age.

People who have an MTHFR genetic mutation may also be more prone to B12 deficiency. This is because having this particular mutation inhibits the way your body can process B vitamins, including folate and B12.

Additionally, people who follow a diet that excludes animal products are at a higher risk. This is because, for many people, the most abundant food sources of B12 are animal products.

Vitamin B12 Sources & Absorption

Plant-based eaters generally can’t remedy a B12 deficiency simply by more veggies. While a whole foods, plant-based diet can provide optimal levels of almost all of the nutrients you need, vitamin B12 is one of the only ones that isn’t easily sourced from plants.

The dietary sources of vitamin B12 include:

• Most animal products (for those who eat them), including fish, beef, poultry, dairy products, and eggs
• Algae, seaweed, and some mushrooms
• Some fermented foods like tempeh, kimchi, sauerkraut, and miso
• Fortified foods like certain plant-based milks and yogurts, some cereals, nutritional yeast, and tofu

Some root veggies, like carrots, potatoes, and turnips, were traditionally considered to be decent sources of vitamin B12 due to the healthy soil they were once grown in. However, with so much food grown in relatively “dead” and degraded soils, and with most of us today cleaning our produce thoroughly before we eat it, these foods are no longer reliable sources of B12.

While they may provide some vitamin B12, and it’s also possible that bacteria in your gut are taking care of your needs completely, B12 is too important to leave to chance. If you follow a plant-based diet, it’s important to include a B12 supplement to meet your needs.

Vitamin B12 Supplements

Taking a B12 dietary supplement is necessary for plant-based eaters. But considering how many omnivores are deficient in it, it might be advisable for other people, too. Vegan B12 is easy to find and is one of the least expensive supplements on the market.

But there are several different forms of B12 supplements available. So which one is best? Believe it or not, some natural health advocates get remarkably heated on this topic.

Cyanocobalamin vs Methylcobalamin

The most widely used form is cyanocobalamin, mainly because it’s cheaper and more stable to manufacture than other forms. When you ingest cyanocobalamin, your body converts it into one of the two active forms of vitamin B12: methylcobalamin or adenosylcobalamin. And some studies indicate that cyanocobalamin may be better absorbed, so score one for team cyanocobalamin.

But the next most popular form is methylcobalamin, which is the natural form (the kind found in food sources), whereas cyanocobalamin is synthetic. And some studies have found that, compared to methylcobalamin, more cyanocobalamin is excreted through urine, suggesting that methylcobalamin may be retained better.

Some people also rail against cyanocobalamin by explaining that it is made with cyanide (a poisonous substance). And it’s true that cyanocobalamin does include a cyanide molecule. But the good news is that even at a high dose, you’ll still be getting a thousand times less cyanide than is toxic. And the tiny amount of cyanide is excreted in the urine. So while this sounds terrible, it probably isn’t cause for alarm. Even if you don’t have the constitution of Rasputin, you will not get poisoned.

That said, if the cyanide factor makes you want to opt for methylcobalamin, I won’t blame you. Overall, available research around vitamin B12 suggests that the differences in bioavailability between these two forms may not be enough to suggest one over the other for most people. Instead, factors that affect the absorption of vitamin B12, like age and genetics, may be more influential than the form of the supplement itself.

Supplement Amounts

How much vitamin B12 should you take in the form of a supplement? Generally speaking, it’s best to get your levels tested to determine your baseline and adjust dosages accordingly.

The registered dietitians at VeganHealth.org, who have extensively researched vitamin B12 on a vegan diet, put together a helpful table with recommended regimens for supplementing vitamin B12. You can see that table here.

Vitamin B12 injections are another option. Such injections are most often used for high-risk people who have absorption issues, and for people who are already vitamin B12 deficient. The advantage of this method is that it can quickly correct low levels of B12. Injections generally contain high levels of cyanocobalamin and can either be self-administered or given by a physician.

Vitamin B12 Risks and Interactions

In general, high doses of B12 are considered safe with a low risk of toxicity, and there is no established upper tolerable limit for this nutrient. If you’re taking an oral supplement, there’s no known risk with taking a reasonable amount daily, even if you haven’t had your blood levels checked.

However, there may be some risks to B12 injections, which is why they should not, in most cases, be undertaken without support from a qualified healthcare professional. If you’re allergic to cyanocobalamin or cobalt, have low potassium levels (hypokalemia), kidney disease, a rare blood disorder called polycythemia vera, the eye disease Leber’s disease, or nutrient deficiencies like iron or folic acid, B12 injections are not recommended due to higher risk for interactions.

Vitamin B12: Essential and Non-Negotiable

Vitamin B12 is an essential vitamin that’s necessary for good health. Plant-based eaters and older people are at increased risk of deficiency. Fortunately, even if you opt to forego all animal products, you can get all the B12 you need, and all the benefits from this versatile and critical nutrient, with a simple and affordable supplement.

Fonte: Food Revolution Network

As informações e sugestões contidas neste blog são meramente informativas e não devem substituir consultas com médicos especialistas.

É muito importante (sempre) procurar mais informações sobre os assuntos