Given the popularity of Veganuary this year I thought it was time to write my follow up blog on plant based diets. The vegan movement is growing rapidly but I feel its not a lifestyle that should be adopted blindly. An optimal vegan diet needs to include plenty of fruit, vegetables, whole grains, legumes and fortified foods to achieve an optimal nutritional status. It is also important to supplement some nutrients as these either cannot be obtained in adequate amounts from vegan sources or are only present in animal products.
Here’s what you need to know about vegan nutrition and what you may be lacking:
- Just because a product is animal free it doesn’t mean it’s healthy. For example, sweetened almond milk is high in sugar so it is best to opt for unsweetened dairy free milks. Many other vegan products such as soy protein burgers, mince and cheeses are all highly processed and are either high in calories or lack nutrients. These should only be consumed in moderation.
- Vitamin B12 – deficiency of this nutrient is extremely prevalent regardless of dietary pattern, particularly in older adults, due to malabsorption. Deficiency can result in anaemia. If severe it can cause irreversible nervous system damage. Well balanced vegan diets are rich in folic acid and this can mask B12 deficiency so it is vital vegans obtain B12 from reliable sources. Fortified milks, seaweed such as nori, and nutritional yeast are good sources. However, in many other plant foods B12 is either present in an inactive form and cannot be absorbed or quantities are too variable so cannot be relied upon (1). We only require vitamin B12 in relatively small amounts but to avoid deficiency I would recommend supplementation of 10mcg a day or 2000mcg per week.
- Iodine – this important mineral is required for the production of thyroid hormones, which control your metabolism. Seaweed is a good animal free source but given consumption is low most vegans need to supplement.
- Essential Fatty Acids – these omega 3 and omega 6 fatty acids are essential because the body cannot synthesise them; they must be obtained from the diet. Vegan diets are usually rich in omega 6 but often lack omega 3. This can result in an imbalance from excessive amounts of omega 6, creating an inflammatory environment in the body (also see Louise’s blog about fat!). The omega 3 fatty acid alpha linolenic acid (ALA) is converted to more physiologically active eicosapentoic acid (EPA) and docosahexanoic acid (DHA). ALA is present in walnuts and flax, chia and hemp seeds. However studies have shown that non-animal dietary sources of omega 3 are poorly converted to EPA and DHA (2). It is worth considering an algae oil supplement providing EPA and DHA. Research has shown this to be beneficial for balancing EPA and DHA in vegans (3).
- Iron – is required for the formation of haemoglobin, which transport oxygen around the body. It also plays a role in energy production and immunity. Plenty of plant foods contain iron so make sure you include them: pumpkin seeds, chickpeas, raisins, tofu, almonds, prunes, cashew nuts, beans, chia seeds and quinoa. Vitamin C helps to enhance the absorption of iron from plant sources so try eating iron rich foods with those rich in vitamin C such as peppers and broccoli.
- Zinc – is required for many cellular reactions, healthy skin and proper functioning of the immune system. Whilst it is possible to get adequate zinc from plant sources, the high intake of phytates from grains in a vegan diet can inhibit zinc absorption. Make sure you consume plenty of beans, chickpeas, tofu, walnuts and pumpkin seeds!
- Selenium – is an important antioxidant and is required for many reactions within the body. Eating 2-4 brazil nuts per day can provide your daily requirement for selenium. However the selenium content is extremely variable so it is worth considering supplementing, ideally as part of a vegan multi-vitamin.
- Vitamin D – required for regulation of the immune system and healthy bones by controlling calcium levels. It is a common deficiency for both meat-eaters and vegans. However, as a vegan food sources are extremely limited so make sure you get out in the sun between April and September and take a supplement during the winter months!
Monitoring your nutrient status is advisable, especially when vegan. Your GP will check B12, Vitamin D and Iron (and ideally ferritin- iron stores) annually upon request, but will not check any of the others. All of the mentioned nutrients (B12, vitamin D, iron, iodine, EFAs, zinc, and selenium) can be checked at our clinic.
If you are new to veganism and want further advice on achieving plant-based optimum nutrition, why not book an appointment at the clinic and we can give you tailored advice!
1. Watanabe F, Yabuta Y, Bito T, Teng F. Vitamin B12-Containing Plant Food Sources for Vegetarians. Nutrients [Internet]. 2014 [cited 18 February 2018];6(12):1861-1873. Available from: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4042564/
2. Lane K, Derbyshire E, Li W, Brennan C. Bioavailability and Potential Uses of Vegetarian Sources of Omega-3 Fatty Acids: A Review of the Literature. Critical Reviews in Food Science and Nutrition [Internet]. 2013 [cited 18 February 2018];54(5):572-579. Available from: https://www.ncbi.nlm.nih.gov/pubmed/24261532
3. Sarter B, Kelsey K, Schwartz T, Harris W. Blood docosahexaenoic acid and eicosapentaenoic acid in vegans: Associations with age and gender and effects of an algal-derived omega-3 fatty acid supplement. Clinical Nutrition [Internet]. 2015 [cited 18 February 2018];34(2):212-218. Available from: http://www.clinicalnutritionjournal.com/article/S0261-5614(14)00076-4/abstract