Dietary supplements are no substitute for a healthy diet. The dietary recommendations used for the Global Burden of Disease Study 2017 (see the Table in this paper) included the avoidance of excess salt and processed meat, and the daily consumption of at least 125 g of whole grains, 250 g of fruit (3 portions), 20 g of nuts and seeds, 400 g of vegetables (5 portions, including one of legumes), and 250 mg (milligrams) of long-chain omega-3 fatty acids (EPA and DHA). Failure to meet these recommendations is estimated to account for about 90% of diet-related health impacts both globally and in the UK. It can be seen that these recommendations are readily met on a vegan diet, with the possible exception of that relating to an adequate intake long-chain omega-3 fatty acids, of which more below.
Nevertheless, there are some nutrients that present a problem for vegans, and we recommend that vegans supplement their diet with the following:
- Vitamin B12 (10 micrograms daily supplement or 2000 micrograms once per week)
- Vitamin D (20 micrograms vegan vitamin D3 a day all year round unless confident of adequate sun exposure)
- Iodine (75 to 150 micrograms a day)
- Selenium (30 to 60 micrograms a day)
- Long chain omega-3 fatty acids (250 mg a day of a mixture of EPA and DHA or a good balance of plant omega-3 and omega-6)
- Calcium (enough to ensure 500 mg a day from supplements and rich bioavailable food sources combined).
The first four vitamins and minerals listed above are conveniently and inexpensively provided by a daily tablet of the VEG-1 nutritional supplement available from the Vegan Society. The Vegan Society recommend that vegans either supplement their diet with vitamin B12 or get at least 3 micrograms per day from fortified foods such as some plant milks and breakfast cereals, yeast extracts and nutritional yeast flakes. The main source of vitamin D is the action of sunlight on skin, with marked seasonal variation in blood levels. In the UK the sun is too low in the sky to be an adequate source between October and February, so Public Health England recommend taking 10 micrograms a day in autumn and winter, whilst noting that some people will need more than this. Vegan vitamin D3 may be better absorbed than the fungal-derived vitamin D2. Iodine and selenium are found in some plant foods (especially kelp and Brazil nuts, respectively) but the content is variable, so obtaining these nutrients from a supplement is a good insurance policy.
VEG-1 does not contain calcium, but calcium supplements are readily available; for example, a tablet of Holland & Barrett Calcium & Magnesium provides 500 mg of calcium (and 250 mg magnesium). Otherwise, good dietary sources of calcium for vegans include kale or spring greens (150 mg per 100 g), broccoli or cabbage (50 mg per 100 g), oranges (40 mg) and fortified plant milks (usually 120 mg per 100 ml, so half of a litre carton provides 600 mg), and calcium-set tofu. However, it should be noted that the recommended intake for calcium is 700 mg per day in the UK, and higher still in the USA and some other countries, so it might be wise to take calcium supplements as well as ensuring a calcium-rich diet.
Long chain omega-3 fatty acids present more of a problem for vegans (and to a lesser extent vegetarians) because the most readily available dietary sources are oily fish. Therefore, vegans must either take a supplement (for example, Vegetology Opti-3) or rely on the conversion of alpha-linolenic acid (ALA) in the body to the long chain forms EPA and DHA. This option can be as simple as replacing oils high in omega-6 fatty acids (such as sunflower and soya oil) with rapeseed or hempseed oils and favouring nuts such as cashews, almonds, walnuts and hazel nuts over seeds such as sunflower and sesame (tahini) in order to achieve an overall ratio of omega-6 to omega-3 fatty acids of around 4:1. Flaxseed oil is 55% ALA, but it requires refrigeration and is not recommended for use in cooking.