Vegan Diets: Do Supplements Fill Nutritional Gaps?

It is a common misconception that vegans are immune from nutrient deficiencies. While a vegan diet is associated with lower blood pressure, lower blood cholesterol, and lower risks of heart disease, stroke, and diabetes, it does not provide immunity against all disease or guarantee excellent nutrition or perfect health. A well-planned vegan diet can be perfectly healthy, but it is important to be mindful of getting all the nutrients your body needs.

There are several nutrients that vegans commonly fall short on, including calcium, zinc, vitamin B12, vitamin D, and omega-3 fatty acids. For example, vitamin B12 is essential for normal brain function and a healthy nervous system, but there are no naturally occurring plant-based sources of B12. As a result, vegans may need to consider taking supplements to ensure they are getting all the necessary nutrients.

Vitamin B12

The daily recommended intake is 2.4 mcg per day for adults, 2.6 mcg per day during pregnancy, and 2.8 mcg per day while breastfeeding. The less frequently you ingest vitamin B12, the more you need to take. So, vegans who are unable to reach the recommended daily intake using fortified foods should opt for a daily supplement providing 25–100 mcg of cyanocobalamin or a weekly dosage of 2,000 mcg.

Vitamin D

During spring and summer, many people in the UK can get this 'sunshine vitamin' through skin exposure to sunlight. However, vitamin D supplementation is recommended from October to March as a minimum and year-round for certain groups, including people with darker skin and those who do not often expose their skin to sunlight.

Calcium

While dairy products are often touted as the best source of calcium, there are plenty of vegan-friendly sources of this mineral. Plant sources of calcium include bok choy, kale, mustard greens, turnip greens, watercress, broccoli, chickpeas, calcium-set tofu, and fortified plant milks or juices.

However, studies suggest that most vegans do not get enough calcium. This may be due to the fact that many plant sources of calcium, such as spinach, Swiss chard, and beet greens, contain high levels of oxalates, which can bind to calcium in the gut and inhibit its absorption. Boiling these vegetables can help reduce oxalate levels and improve calcium absorption.

Fortified foods are another good way for vegans to increase their calcium intake. Some foods that are often fortified with calcium include plant yogurts, cereals, flour, cornmeal, and plant milks.

If you are unable to meet your calcium needs through diet alone, supplements can be a safe and effective way to increase your intake. A calcium supplement of about 500 mg per day is generally considered safe and can help you meet the recommended daily intake. However, it is important not to exceed the upper limit of 1,300 mg per day, as too much calcium can increase the risk of kidney stones.

In addition to calcium, vitamin D is also crucial for bone health, as it helps enhance the absorption of calcium in the gut. Spending time in the sun and consuming fortified foods or taking supplements can help ensure adequate vitamin D intake.

Finally, weight-bearing exercise, such as weight lifting or walking, can also help improve bone health by increasing the performance of osteoblasts and osteoclasts, the cells responsible for maintaining bone strength.

Iodine

The recommended daily iodine intake for adults in the UK is 140 mcg. For pregnant women, this increases to 220 mcg, and for those who are breastfeeding, it is 290 mcg.

Iodised salt is not a great option, as health authorities recommend reducing salt intake. Instead, vegans can ensure they get enough iodine by consuming iodine-fortified milk alternatives (around 500ml per day) or taking a daily supplement containing potassium iodide or potassium iodate.

There are concerns that some groups in the UK are not meeting the recommended iodine intake, including vegans. Iodine deficiency can lead to hypothyroidism, causing low energy levels, dry skin, tingling in hands and feet, forgetfulness, depression, and weight gain.

It is important not to consume too much iodine, as this can also lead to thyroid problems.

Selenium

The amount of selenium in a plant food varies depending on how much was in the soil the food was grown in. Selenium content can also vary based on where a plant was grown, so vegans in Europe may have lower intakes than those living in countries with higher soil selenium or extensive use of high-selenium imported produce, such as vegans in Canada and the US.

The Recommended Dietary Allowance (RDA) for adults in the United States is 55 micrograms of selenium per day. This amount should be enough for most people, although selenium requirements increase to 60 micrograms per day during pregnancy and 70 micrograms per day during breastfeeding.

The best vegan sources of selenium include certain nuts, seeds, mushrooms, whole grains, and legumes. Brazil nuts are the richest source of selenium, with a single nut providing more selenium than the recommended daily amount. However, because they are so high in selenium, it is best to limit consumption to one or two Brazil nuts per day to avoid selenium toxicity, which can cause hair loss and brittle nails. Other good sources of selenium include enriched pasta, brown rice, cremini mushrooms, sunflower seeds, portabella mushrooms, chia seeds, firm tofu, barley, and whole wheat bread.

While it is possible to get enough selenium through diet alone, taking a selenium supplement is a reliable way to guarantee an adequate intake and prevent selenium deficiency.

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