Cutting meat from one’s diet has become increasingly popular for a number of reasons, including health and environmental concerns.

Vegan diets are characterized by the avoidance of animal products, including meat, eggs, and dairy. A vegan diet brings with it a unique set of nutritional and health considerations.

The vegan ethos

The vegan diet is particularly popular among younger people, and especially women. In 2006, 1.4% of the US population was vegan, and this increased to

3.4% by 2015.

The central idea around veganism is to avoid animal-based foods due to environmental reasons, ethical concerns regarding the treatment of farm animals, the use of chemicals such as growth stimulants in farm animals, and health advantages.

While the general plant-based contents of veganism hold true, there are several choices vegans can make, which are often influenced by their reason for becoming vegan.

The most extreme are those who eat so-called “living food”, which is uncooked vegan food such as seeds, vegetables, and nuts.

A large number of possible variations in what it means to be vegan can make it challenging to study how veganism impacts health.

Effects of veganism

Research on the effects of vegan diets has primarily focused on two areas: health and environmental impact.

Health studies show that vegan diets are associated with being thinner, having lower cholesterol, and having lower blood pressure, among other health benefits. This is primarily attributed to both food intake and modulation of the gut microbiome. However, long-running studies establishing the actual effectiveness of the diet and separating the effects from other factors are lacking.

Similarly, it can be challenging to assign a validated correct value to the environmental burden of meat-eating.

Several international collaborations have shown that food can be a massive emitter of greenhouse gases through production, transport, storage, cooking, and waste.

Reasons include inefficient use of land, both in terms of grazing animals and in the food used to feed livestock and methane released by livestock.

Studies that have compared meat eaters to vegans and vegetarians have estimated that meat-eaters have a carbon footprint that is more than double the footprint of vegans.

Specifically, meat-eaters are estimated to have greenhouse gas emissions of 7.19 kgCO₂e/day compared to 2.89 kgCO₂e/day for vegans. Therefore, there is some support that vegan diets can be effective for individuals who change their diet for environmental reasons.

Recommendations for vegans

Because a lot of commonly consumed nutrients from meat and dairy are omitted from a vegan diet, there are some dietary recommendations for vegans that are generally made. These can be in the form of natural sources, fortified foods, or through pill supplements.

Among vitamins, B12 and D are advised to be supplemented since it is not found in a vegan diet. Foods can be fortified with B-12 to allow vegans to consume B-12 as part of their regular diet, in foods such as fortified soy beverages and nutritional yeast. Vitamin B12 may also added to some breakfast cereals. Vitamin D can be found in drinks such as orange juice.

Other essential nutrients that usually need to be supplemented in a vegan diet are calcium and zinc. While calcium is common in many staple vegan foods such as leafy green vegetables and tofu, it usually needs to be complemented with calcium-fortified foods such as fruit juices.

Zinc is also common in many vegan staples, such as grains and legumes, but vegans should be careful to consume enough of these to balance out the high phytate content of a classic vegan diet.

Healthy fatty acids, such as omega-3, is common in fish, and thus often missed out on in vegan diets.

Vegans are recommended to eat foods rich in n-3 fatty acid ALA, such as walnuts and soy products, and n-3 fatty acid DHA, such as soy milk and cereal bars. This is especially important for pregnant and lactating women, who may wish to use additional supplements of long-chain n-3 fatty acids.

Sources

1. W.J. Craig (2009) Health effects of vegan diets. The American Journal of Clinical Nutrition.https://doi.org/10.3945/ajcn.2009.26736N
2. Scarborough, P. et al. (2014) Dietary greenhouse gas emissions of meat eaters, fish eaters, vegetarians and vegans in the UK. Climatic Change. https://doi.org/10.1007/s10584-014-1169-1
3. Medawar, E. et al. (2019) The effect of plant-based diets on the body and the brain: a systemic review. Translational Psychiatry. https://doi.org/10.1 038/s41398-019-0552-0

Last Updated: Feb 23, 2020 Adapted from

Sara Ryding Sara is a passionate life sciences writer who specializes in zoology and ornithology.She is currently completing a Ph.D. at Deakin University in Australia which focuses on how the beaks of birds change with global warming.

The Best Sources of Vitamin D For Vegans

Stephanie Eckelkamp

https://www.imaware.health/blog/the-best-sources-of-vitamin-d-for-vegans

An estimated one billion people worldwide, and about 42 percent of adults in the United States, are deficient in vitamin D, according to recent scientific research studies. That’s a big problem, since this nutrient is crucial for everything from normal bone growth to regulating immune function to proper glucose metabolism to reducing inflammation. In fact, nearly all of our body’s tissues have receptors for this essential vitamin, so low vitamin D levels over time can have a widespread negative effects on a person’s health.

Achieving optimal vitamin D levels is tricky, though. While humans have the ability to synthesize vitamin D when our skin is exposed to sunlight, increasingly indoor lifestyles make this a difficult feat—unless you live in a sunny place (close to the equator) and spend plenty of time outdoors. Additionally, dietary vitamin D is only naturally found in a few foods—most of which are animal-based, like fatty fish, cod liver oil, egg yolks, cheese, and beef liver. So it should come as no surprise that a person’s diet is more likely to lack vitamin D if it’s 100% plant-based, or vegan.

So, what’s an herbivore to do? Is it possible for a vegan to get enough vitamin D without resorting to animal products? (Spoiler: Yes!). Below, we cover the 7 best strategies to optimize vitamin D levels on a vegan diet, plus how to tell if you’re low in the first place.   

Why is vitamin D so important?

Because vitamin D receptors are found on so many cells throughout the human body, this nutrient plays a crucial role in regulating thousands of vital biological pathways. Either with an at-home vitamin D test or through routine blood work with your physician, it’s important to understand your vitamin D levels and how they can impact your health. 

• Vitamin D helps your body absorb calcium in the gut and helps maintain appropriate blood levels of calcium and phosphate, which allows for normal bone mineralization, bone growth, and bone remodeling, thereby helping prevent conditions like osteoporosis, according to the National Institutes of Health.
• Vitamin D supports optimal immune functioning, and low levels have been associated withincreased risk and severity of respiratory infections in several studies, including a research review published in Clinical & Experimental Immunology. 
• Vitamin D has been shown to help regulate blood pressure and vascular cell growth, while vitamin D deficiency has been associated with arterial stiffening, elevated cholesterol, and other cardiovascular issues, according to research published in the American Heart Association’s journal Circulation. 
• Healthy vitamin D levels have been associated with lower rates of type 2 diabetes, while low vitamin D may contribute to insulin resistance, inflammation, and other factors that increase diabetes risk, according to research published in the journal Endocrinology and Metabolism Clinics of North America. 
• Maintaining healthy vitamin D levels may help reduce the risk and spread of various types of cancer, according to the National Institutes of Health, though more research is needed in this area.
• Low levels of vitamin D have been associated with multiple sclerosis (MS), according to a research review published in Neurology and Therapy; and according to a Cochrane Review on vitamin D and MS, data shows that this disease is far less common near the equator, an area that gets a lot of sunlight. 
• Low levels of vitamin D have been associated with an increased risk of depression and poor mood, according to research published in the British Journal of Psychiatry. Low vitamin D from lack of sunshine is one reason people can suffer from seasonal affective disorder (SAD) in darker winter months.

7 vegan sources of vitamin D

According to the National Institutes of Health, the vitamin D recommended daily intake (RDA) for adults is 600-800 IU per day, “but for vegans, I would go for the max recommended dose of 800 IU,” says E. P. Diamandis, MD, Ph.D, medical biochemistry professor and cancer researcher.  Some people may need more, but avoid ingesting more than 4,000 IU per day—the tolerable upper intake level—unless your doctor recommends it. 

While it’s basically impossible to get enough vitamin D from natural sources on a vegan diet, the following vegan foods (including fortified foods), vegan supplements, and lifestyle habits can help you hit your daily quota. 

1. Vitamin D supplements

Adding vitamin D to your daily supplement regimen is strongly advised if you’re a vegan. You’ll notice two types of supplements on the market: vitamin D2 (ergocalciferol) and vitamin D3 (cholecalciferol). Some research suggests vitamin D3 is a bit more effective at increasing levels of vitamin D in the bloodstream, but other research has found they’re about the same. 

Pro tip: While some vitamin D3 supplements are derived from animal byproducts, you can find plant-based options—be sure to specifically look for vegan vitamin D3, which is often derived from lichen. Vitamin D2 is often manufactured from mushrooms exposed to UV light. 

2. Mushrooms

Mushrooms are the only readily available, natural plant-based food sources of vitamin D. They contain a compound called ergosterol that—upon exposure to UV light—is converted into vitamin D2 (ergocalciferol). In fact, UV-treated mushrooms are approved as a food additive by the Food & Drug Administration as a source of vitamin D2.  

As for whole mushrooms, many don’t contain much vitamin D because they’re grown in dark conditions. However, you can boost their vitamin D content yourself! Vitamin D researchers recommend spreading them out on a baking sheet (gill-side up), covering them in plastic wrap, and then placing the baking sheet outside from 10 a.m. to 4 p.m. so the mushrooms are exposed to the sun’s strongest UV rays. Studies suggests this can yield hundreds to thousands of IUs of vitamin D2, depending on the type of mushroom and length of exposure. According to the National Institutes of Health, a half cup of UV-exposed white mushrooms may contain around 366 IU of vitamin D. 

Additionally, the vitamin D2 present in mushrooms is just as effective at raising blood levels of vitamin D as a supplement, according to a study published in Dermato Endocrinology—and cooking doesn’t degrade the vitamin D in mushrooms either.

3. Fortified plant-based milk

Many, but not all, brands of plant-based milks (think: almond milk, soy milk, rice milk, cashew milk) have been fortified with vitamin D2. Typically, one cup of the milk contains around 5 mcg(or 200 IU), which works out to 25% of the daily value. Just remember to scan the label, as some additive-free brands are not fortified with any additional vitamins. 

4. Fortified cereals

Nearly all mainstream cereals are fortified with vitamins and minerals, including vitamin D. Cheerios, for example, contains 2 mcg (or 80 IU) of vitamin D2, which is 10% of the daily value. Keep in mind, some cereals that are marketed as more natural options, along with most granolas and plain rolled oats, are not fortified. 

5. Fortified orange juice

Not all orange juice is fortified, but you can almost always find an option fortified with vitamin D and calcium. Tropicana Calcium + Vitamin D contains 2.5 mcg (or 100 IU) of vitamin D3. But don’t make juice your go-to source of vitamin D—it’s a significant source of sugar with no fiber to buffer potential blood sugar spikes, so you don’t want to drink it in excess. If you do drink OJ, consider incorporating it into a protein-rich smoothie. 

6. Fortified tofu

Not all tofu is fortified, but some brands contain around 20% of your daily vitamin D, along with vitamin B12 and omega 3 fats—three of the most common nutrient deficiencies in a vegan diet. Tofu can be great because it’s like a blank slate, taking on any flavors you add to it. Combine tofu with spices and herbs to create a delicious tofu scramble in the morning, or marinate and add to a stir-fry for dinner. 

7. Sunshine

While spending too much time in the sun sans SPF is not a good idea for your health, neither is extremely limited sun exposure. It turns out, catching a few minutes of midday rays can go a long way in boosting your vitamin D levels. According to the National Institutes of Health, some researchers believe that 5-30 minutes of sun exposure (to the face, arms, hands, and legs) at least twice a week may lead to sufficient vitamin D synthesis. Just keep in mind: Older adults and people with darker skin tones are less able to produce vitamin D from sunlight, so utilizing the other resources on this list will be key. 

Vitamin D’s best-known role is to keep bones healthy by increasing the intestinal absorption of calcium. Without enough vitamin D, the body can only absorb 10% to 15% of dietary calcium, but 30% to 40% absorption is the rule when vitamin reserves are normal. A lack of vitamin D in children causes rickets; in adults, it causes osteomalacia. Both bone diseases are now rare in the United States, but another is on the rise — osteoporosis, the “thin bone” disease that leads to fractures and spinal deformities.

Low levels of vitamin D lead to low bone calcium stores, increasing the risk of fractures. If vitamin D did nothing more than protect bones, it would still be essential. But researchers have begun to accumulate evidence that it may do much more. In fact, many of the body’s tissues contain vitamin D receptors, proteins that bind to vitamin D. In the intestines, the receptors capture vitamin D, enabling efficient calcium absorption. But similar receptors are also present in many other organs, from the prostate to the heart, blood vessels, muscles, and endocrine glands. And work in progress suggests that good things happen when vitamin D binds to these receptors. The main requirement is to have enough vitamin D, but many Americans don’t.

Symptoms of vitamin D deficiency

If you’re low in vitamin D, you may not notice any symptoms at first, or they may be subtle. According to the Cleveland Clinic, symptoms of vitamin D deficiency may include:

• Fatigue
• Bone pain
• Muscle pain, weakness, aches, or cramps
• Mood changes, like depression
• Slow wound healing
• Getting sick frequently

Taking the steps above, and periodically checking your vitamin D status—with routine blood work from your physician or at-home testing kits—is a good way to ensure that your levels stay in a healthy sweet spot. Not too low and not too high. 

How much vitamin D do I need?

Although it’s unlikely that you’ll overdo it on vitamin D from the sun or food sources, it ispossible if you’re supplementing with very high doses. Never exceed 4,000 IU per day unless directed by your doctor, says Dr. Diamandis. More than this confers no added benefit, and it may be toxic. 

According to the National Institutes of Health, excessive vitamin D intake can lead tohypercalcemia (high levels of calcium in the blood), which, in turn, can cause nausea, vomiting, muscle weakness, pain, poor appetite, dehydration, excessive thirst, kidney stones, and, in extreme cases, kidney failure. So keep tabs on your intake and watch out for these symptoms.

Also keep in mind, vitamin D is a fat soluble vitamin, meaning that it’s better absorbed by your body when you take it with a fat-containing meal. 

Bottom line

Vitamin D is important for way more than keeping your bones healthy—but it’s really tricky to obtain adequate vitamin D on a strictly vegan diet. Fortunately, it’s possible to hit your daily quota by prioritizing safe sun exposure, taking a daily vitamin D supplement, and consuming the right foods. Taking these steps, and regularly monitoring your vitamin D levels, is a vital step in ensuring bone health, cardiovascular health, optimal immune function, mental health, and more.

What is vitamin D?

Vitamin D is not one chemical but many. The natural type is produced in the skin from a universally present form of cholesterol, 7-dehydrocholesterol. Sunlight is the key: Its ultraviolet B (UVB) energy converts the precursor to vitamin D₃. In contrast, most dietary supplements are manufactured by exposing a plant sterol to ultraviolet energy, thus producing vitamin D₂. Because their function is almost identical, D₂ and D₃ are lumped together under the name vitamin D — but neither will function until the body works its magic (see figure).

How your body makes vitamin DThe sun’s energy turns a chemical in your skin into vitamin D3, which is carried to your liver and then your kidneys to transform it to active vitamin D.

The first stop is in the liver, where vitamin D picks up extra oxygen and hydrogen molecules to become 25-hydroxyvitamin D, or 25(OH)D. This is the chemical that doctors usually measure to diagnose vitamin D deficiencies. But although 25(OH)D is used for diagnosis, it can’t function until it travels to the kidney. There it acquires a final pair of oxygen and hydrogen molecules to become 1,25 dihydroxy vitamin D; scientists know this active form of the vitamin as 1,25(OH)₂D, or calcitriol, but for ordinary folks the name vitamin D is accurate enough.

How it works

Vitamin D’s best-known role is to keep bones healthy by increasing the intestinal absorption of calcium. Without enough vitamin D, the body can only absorb 10% to 15% of dietary calcium, but 30% to 40% absorption is the rule when vitamin reserves are normal. A lack of vitamin D in children causes rickets; in adults, it causes osteomalacia. Both bone diseases are now rare in the United States, but another is on the rise — osteoporosis, the “thin bone” disease that leads to fractures and spinal deformities.

Low levels of vitamin D lead to low bone calcium stores, increasing the risk of fractures. If vitamin D did nothing more than protect bones, it would still be essential. But researchers have begun to accumulate evidence that it may do much more. In fact, many of the body’s tissues contain vitamin D receptors, proteins that bind to vitamin D. In the intestines, the receptors capture vitamin D, enabling efficient calcium absorption. But similar receptors are also present in many other organs, from the prostate to the heart, blood vessels, muscles, and endocrine glands. And work in progress suggests that good things happen when vitamin D binds to these receptors. The main requirement is to have enough vitamin D, but many Americans don’t.

Vitamin D deficiencies

Vitamin D deficiencies were rare when most men rolled up their sleeves to work in sunny fields. But as work shifted from farms to offices, that changed. Because pigmentation can reduce vitamin D production in the skin by over 90%, nonwhite populations are at particular risk. Deficiencies are also common in patients with intestinal disorders that limit absorption of fat and those with kidney or liver diseases that reduce the conversion of vitamin D to its active form, calcitriol (1,25(OH)2D). In addition, certain medications reduce the availability or activity of vitamin D. And even in healthy people, advancing age is linked to an increased risk of vitamin D deficiency.

Although standards vary, most experts agree that levels of 25(OH)D below 20 ng/ml (nanograms per milliliter) reflect clear-cut vitamin D inadequacy, while levels between 20 and 30 ng/ml are borderline.