Updated: Aug 20, 2021
Interest in veganism has quadrupled in the last five years, to some extent driven by ethical and climate concerns, but the science is clearthat eating more plants in the form of fruits, vegetables nuts, seeds and wholegrains is hugely beneficial to our health. However, the UK National Nutrition and Diet Survey found that significant members of the vegan population are low in Omega-3 fatty acids, Vitamin D, Vitamin B12, iodine and iron (particularly women and teenage girls).
Adequate protein intake can also be an issue for vegans, in ensuring the full spectrum of amino acids are consumed, such as lysine found in soya, lentils, pistachios and pumpkin seeds. As a general rule, twice the volume of protein is needed from plant foods to obtain an adequate RDA of 0.75kg per body weight, compared to animal products.
Omega-3 fatty acids found in oily fish are anti-inflammatory and essential to maintain good health (they cannot be made by our bodies), particularly the heart and brain. Flax and chia seeds are a source of the parent omega-3 Alpha-linolenic acid, however conversion to the useable forms of DHA and EPA is around 2-10%. Omega 3 is also affected by the levels of Omega-6 in the diet (sunflower oil, spreads and processed foods), and levels of co-factor minerals such as magnesium and zinc. The ideal ratio of Omega 3-6 oils is 2:1, but several studies have suggested vegans are deficient in Omega 3.
Low Vitamin D is likely prevalent across the whole UK population as we make the superior form D3 from the sun on our skin, especially during winter months. The D2 form is found in meat fish and eggs, with government guidelines changed in 2016 to suggest we all take 10 micrograms daily by way of supplementation. Vegans should look to mushrooms and fortified foods, or supplements.
Vitamin B12 is primarily found in animal foods, needed for energy and the nervous system. Low levels have been associated with fatigue, pins and needles, depression and memory, and has long term deficiency has implications for anemia, heart and brain health. Whilst processed foods can be fortified with this vitamin, supplementation is often recommended for vegans, particularly as we age and absorption of vitamins and minerals can decline.
Iodine is necessary for good thyroid health, and cannot be stored in the body for a long period so must be obtained regularly from the diet. The thyroid gland is crucial for maintaining a healthy metabolism so if intake is inadequate or excessive it can cause problems systemically through the body. Iodine is not routinely added to salt in the UK, and because fish and diary are the richest sources, vegans can look to seaweed or supplements.
Non-heme sources of iron from plants have a lower absorption rate in the body of 2-7% compared to 12-25% from animal sources, so vegans may need to increase their quantity of iron rich foods, combining with Vitamin C rich foods and avoiding caffeine when eating.
Calcium needed for strong bones is often associated with dairy, though is found in vegan sources such as kale, broccoli, rocket, chickpeas. Fortified non-diary milks such as coconut, almond and soya milk are popular and helpful, as higher fracture rates have been found in vegans, and deficiency may take a long time before symptoms are shown.
Finally, a word of warning as the food industry has matched the interest in veganism with many processed foods labelled as vegan, from breakfast cereals to ready meals which don’t necessarily equate to good health. Hydrogenated fats are likely in these products, oils which have been heated, which cause free radicals in the body, causing inflammation and dysregulated cell signaling. Try to eat whole fresh foods, where possible.