Updated September 10, 2020

Taking supplements has long been a controversial topic. For those of us centering our diet around unprocessed plant-based foods (fruits, veggies, whole grains, legumes, nuts and seeds) here are some things to consider.

Are multivitamins beneficial?

A 2013 review of 26 vitamin and mineral supplementation studies found no consistent evidence that the supplements affected cardiovascular disease, cancer, or any cause of death in healthy individuals without known nutritional deficiencies.

Multivitamins without iron and copper

For those who take multivitamin supplements, opt for those without iron and copper.

If you have a blood test showing you are anemic, iron supplements can be helpful. However, excessive amounts iron in supplements are best avoided. This is, in part, because iron is a pro-oxidant, and can induce oxidative stress (one study here). Oxidative stress is thought to be involved in many diseases. The average iron status of vegan groups has been shown to be adequate in studies such as this one. And vegan intakes of copper are more than adequate. Copper is also a pro-oxidant, which is why copper supplements are best avoided.

Check out this very interesting 4-minute video about the potential association of high copper (and iron) intake with Alzheimer’s.

Vitamin B12

A reliable source of vitamin B12 is critical for anyone eating a plant-based diet. It is an essential nutrient, involved in DNA synthesis and produced mainly by bacteria. Among other places, bacteria grow in the guts of animals and therefore eating animals and animal products can be a good source of B12. Vegans may once have obtained the needed B12 by drinking out of mountain streams or well water (herbivorous primates get B12 by ingesting bugs, dirt and feces). Because plants are not a reliable source of B12, vegans must turn to fortified foods (e.g. some nutritional yeast products, cereals, non-dairy beverages, mock meats) and/or supplements.

Michael Gregor, MD advises here taking at least 2,000 mcg of B12 (specifically cyanocobalamin) once each week (or 50 mcg per day), ideally as a chewable, sublingual, or liquid supplement. He also notes in his book, How Not to Die, that as we age, our ability to absorb B12 may decline. Therefore, if we are over the age of 65 and on a plant-based diet, he recommends 1,000 mcg/day of cyanocobalamin. Any excess is eliminated so there is no risk of taking too much.

Check out Part 2 of this blog for guidance on Vitamin D, essential fatty acids and iodine.