The 10 Best Green Supplements & Their Benefits

by Joel Kahn, M.D.

Photo: Darren Muir

After 30 years of advising patients of the health benefits of a plant-based diet, I still worry that they may choose a junk food route that may leave them lacking essential nutrients. There are a variety of foods that carry the vegan label but are unlikely to promote health, and many people may start with these on their vegan journey. For example, both Taco Bell and White Castle are promoting plant-based options that may be better than the industrial meats they serve but are a long way from a bean and avocado salad topped with sprouts. And while some processed vegan meals may work in a pinch or as a splurge, the mainstay of a healthy vegan eating pattern must be whole foods with single ingredients. The focus on staples like fresh fruits, vegetables, legumes, whole grains, nuts, and seeds is an awesome path to preventing and even reversing many disease processes.

In addition to eating processed junk food too often, another dietary trap vegans can fall into is ignoring the need to supplement their meals. This is important to gain all of the benefits of a diet free of animal products. The status of modern farming and the subsequent creation of soil depleted of nutrients may result in low vitamin intake. Most of the adults I see in my clinic, whether they are eating a diet that is vegan or otherwise, lack important nutrients on the advanced testing I perform. The following list is what I suggest to my patients following a plant-based diet to maximize health and vitality:

1. Vitamin B12:

Vitamin B12 is important in brain, nerve, and hematologic health and is a factor in a key process called methylation. Methylation regulates homocysteine levels and plays an important role in the control of DNA regulation. Neither plants nor animals make B12; it's produced by bacteria that reside in the gastrointestinal tract of animals other than humans. When animal products are eaten, B12 is ingested as a bystander. When we wash our produce, we wash off the B12-rich bacteria.

By some estimates, 50 percent of vegans and 10 percent of vegetarians are deficient in vitamin B12. I recommend taking about 2,500 ug once a week, ideally as a liquid, sublingual, or chewable form for better absorption or 250 ug daily if that schedule works better for you. There is no known risk to taking larger amounts of B12.

2. Vitamin D:

Vitamin D is known to promote bone health and is proving to be essential in blood pressure and blood glucose control, in heart function, and in brain health. Measurements of blood levels are the best way to assess adequate amounts of vitamin D. In a study of over 65,000 residents of England, researchers found that vegans had higher levels of fiber, magnesium, and vitamins E and C compared to their carnivorous counterparts but had lower levels of vitamin D.

Direct sunshine on exposed skin for 20 to 30 minutes a day can provide adequate vitamin D, but, for many of us, oral supplementation is necessary. Vitamin D3 is the form most commonly recommended but is usually derived from animal sources such as lanolin. There are vegan versions of D3 now available, and the standard recommendation is to supplement with 800 IU a day, but I start routinely with 2,000 IU a day and titrate up to reach blood levels of 50 to 70 ng/mL.

3. Omega-3s:

I check blood levels of omega-3s in my clinic, and deficiencies are common regardless of what type of diet is followed. As oily fish like sardines and salmon aren’t options for vegans, I recommend supplementing with omega-3 in the form of a combined DHA and EPA (the fatty acids that are great for heart and brain health) supplement sourced from algae. I suggest that most patients on a vegan diet take at least 250 mg each day and some newer brands have 450 mg in a single capsule. At the same time I recommend limiting foods rich in omega-6, which may contribute to inflammation. These are mainly in the forms of oils such as corn, soy, safflower, sunflower, and vegetable oil blends. Overall, I recommend using little or no oil for cooking. Finally, adding whole foods rich in ALA, the precursor to EPA and DHA, is a daily habit I really encourage. This is easy to accomplish using 1 to 2 tablespoons a day of ground flaxseeds, in addition to a small handful of walnuts, chia seeds, and leafy greens.

4. L-carnitine:

L-carnitine plays an important role in shuttling fatty acids across membranes to fuel the production of energy in the heart and other muscles. L-carnitine is found mainly in meat (think carne) and vegetarians have lower levels of L-carnitine in their muscles. There are rare reports of heart disease in patients lacking this amino acid. Although long-term studies of L-carnitine supplementation in vegans are not available, I consider supplementing vegans with 500 mg a day as a recommendation for optimal health—particularly in those who are athletic or who have heart disease. Recently, L-carnitine in red meat has been shown to be capable of leading to the creation of TMAO, a molecule I measure in the blood of patients, and that is unfavorable for artery health. I advise patients eating meat, and those taking L-carnitine supplements, to stop both habits if their level of TMAO is elevated.

5. Taurine:

Taurine is the most abundant amino acid in the body, and you've probably never heard of it beyond the world of energy drinks. Taurine is important for proper functioning of cardiac immune systems, insulin action, hearing, and electrolyte balance. It is typically found in meat and seafood. Vegans can have low levels of taurine, so supplementation with 500 mg a day is a great option.

6. Vitamin K2:

Vitamin K2 directs calcium to bones rather than arteries and has been shown to work well when combined with vitamin D to promote strong bones and a healthy heart. It is difficult to find in plant foods. Our bodies can convert the vitamin K1 found in dark leafy greens to K2, but it is uncertain how much is being converted, and measuring blood levels is not routine. As our bodies age, there is a reduction in vitamin K2 production, so it is recommended that adult vegans supplement. This vitamin can be found in foods such as sauerkraut, plant-based kefir, unpasteurized kombucha, vegan kimchi, and natto. There are a number of vegan supplements available providing at least 100 ug of vitamin K2 a day, usually from natto.

7. Calcium:

Calcium does not need to be added as a supplement, but a mindfulness about eating enough foods rich in plant-based sources of calcium is wise. About 600 mg a day of plant foods high in calcium is suggested, and this includes all green leafy vegetables. According to the Harvard School of Public Health, 1 cup of cooked collard greens contains 357 mg of calcium (compared to 306 mg of calcium in dairy milk).

8. Iodine:

Healthy adults need 150 micrograms of iodine a day. A majority of folks get their iodine from iodized salt, one-fourth teaspoon of which gives about 45 percent of the Recommended Dietary Allowance (RDA) for iodine. However, it also has 590 mg of sodium, making it not the best choice as the only source of iodine.

Sea vegetables such as nori, dulse, and alaria are excellent sources of iodine and do not appear to be polluted. Iodine is found in vegetables grown near coastal areas but actual amounts of iodine are not listed on whole vegetables. For those who don’t enjoy seaweed or use iodized table salt, a 150 mcg daily supplement of iodine is recommended, often in a multivitamin. The sea vegetable hiziki should not be eaten due to high arsenic levels, and kelp should be avoided as it tends to have too much iodine.

9. Iron:

All menstruating women should increase their absorption by combining foods rich in iron and vitamin C at meals and should get checked for iron-deficiency anemia every few years. Men should be checked for an iron overload disease like hemochromatosis before they start taking a supplement.

10. Selenium:

Selenium is used in many important chemical reactions in the body, and adequate intake is important in vegans and non-vegans. Northern Europeans may need to take a supplement or eat a daily Brazil nut daily.

Vegan diets are a popular and proven path to good health, and they can also promote a clean planet and avoid contributing to the cruel and inhumane life of animals farmed for human consumption. Moving to a vegan diet is not only supported by thousands of medical research studies, but it is also endorsed by the United Nations, Oxford University, the USDA Food Guidelines, and the Association of Nutrition and Dietitians. Although it may seem a bit of a hassle to be sure that the vitamins listed here are in your plant-based routine, it's important to be a "smart vegan" and make sure you're giving your body everything it needs to function optimally. There are a number of plant-based multivitamins that provide all of these nutrients in a single daily dose that may simplify your plan to be the smart vegan.