Dietary supplements are big business, bringing in more than 25 billion dollars a year. If you’re eating a well-balanced plant-based diet, though, you can minimize your own contribution to that industry. With a couple of exceptions, it’s possible to get all the nutrients you need from plant foods. But in a few areas, supplements (or fortified foods) can give some helpful insurance.

Vitamin B12: An essential supplement for people on a plant-based (vegan) diet

So much has been written about vitamin B12 that it often leaves vegans thinking there is some controversy over this nutrient. There isn’t, though. All experts agree that vegans need to supplement with B12, unless they regularly consume foods fortified with it. You can’t get enough by eating organic vegetables or by consuming fermented soyfoods, spirulina or sea veggies. Anyone on a plant-based diet needs a daily supplement of 25 to 100 micrograms, or 1,000 micrograms twice per week (The recommended dose increases dramatically the less often you supplement, because of lower absorption rates). It’s a good idea to opt for a supplement that is chewable or will dissolve beneath your tongue. You can get enough B12 from foods if you are eating at least 2 servings per day of foods that are fortified with 1.5 or more micrograms of B12.

Vitamin D: An important supplement for all

A few animal foods provide vitamin D, but most non-vegans depend on the same sources as vegans: fortified foods or sunshine. And fortified foods actually contain too little to meet recommended daily needs. You can get your daily dose of vitamin D by exposing skin to sunlight for 15 to 30 minutes during midday on a day when sunburn is possible (the darker your skin or the older you are, the more exposure you need). For many people, this isn’t possible in the winter, so a daily supplement of at least 600 IUs is necessary (some experts advise much higher doses than this).

Iodine: Vegetables, supplements or…cleaning solutions?

While milk is not a natural source of iodine, it is often contaminated with it from iodine-containing solutions used to clean cows and milking machines. Those who don’t consume dairy foods need to get iodine from vegetables grown in iodine-rich soil or sea vegetables. The problem is that the amounts vary widely depending on where veggies are harvested and how sea vegetables are processed. As a result, iodized salt remains an important reliable source of this nutrient for everyone. If you use salt in your cooking or on food, choose the iodized type (sea salt is not a reliable source of iodine). Or opt for a supplement providing 75 to 150 micrograms three or four times per week.

Calcium: Supplements can give intake a boost

Research suggests that single large doses of calcium can raise risk for heart disease, so it’s a good idea to use supplements sparingly— small amounts only when you feel like your diet is consistently falling short. Fortunately, it’s not difficult to get enough calcium from plant foods that are either natural sources of this mineral or that are fortified with it.

Omega-3 fats DHA and EPA: An ongoing question for people on a plant-based (vegan) diet

New research suggests that high blood levels of the omega-3 fat DHA are linked to increased risk of prostate cancer. But other studies show that these fats might protect against other chronic diseases. Individuals on plant-based diets typically have lower blood levels of DHA and EPA and we just don’t know how much it matters. It may be helpful for vegans to supplement with a low dose of omega-3s—just 200 to 300 milligrams a few times a week. For those who suffer from depression, higher doses might be recommended, though.

The Bottom Line: vegan and non-vegan supplement needs are not that different

Most meat-eaters or vegetarians look to sunshine or fortified foods like cow’s milk for vitamin D, and at least some of their iodine needs are met only because milk is contaminated with it. Non-vegans are as likely as vegans to depend on supplements to boost their calcium and omega-3 fat intake as well. And whether or not people eat meat, everyone over the age of 50 requires either supplements or fortified foods to meet B12 needs since it becomes harder to absorb this nutrient from animal foods as we get older. No matter what type of diet you eat, small doses of supplements can give a little extra insurance.

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