National Vegetarian Week: Supercharge Your Vegetarian Diet
May 16th marked the beginning of National Vegetarian Week, a campaign aimed at promoting the benefits of a meat-free lifestyle.
A balanced vegetarian diet is an extremely healthy choice. Vegetarians have lower mortality rates than the general population. A balanced vegetarian diet tends to provide higher levels of vitamin C, folate and thiamine than a carnivorous diet. It is also high in fibre, boosting digestive health and potentially lowering the risk of both type 2 diabetes and bowel cancer (1).
Alongside the many benefits of a vegetarian diet, there are also some potential pitfalls. Some essential nutrients are absorbed more poorly in vegetarians, while other nutrients may be less readily available in a meatless diet. Being aware of these factors can help vegetarians to achieve the full health benefits of a meat-free lifestyle.
Iron and Zinc
A balanced vegetarian diet actually contains a fair amount of iron, with iron intakes similar to that of meat eaters. Chickpeas, beans, lentils, whole grains and green leafy vegetables are all good vegetarian sources of iron.
The daily RNI for iron is 14.8mg for women and 8.7mg for men. However, an American study has suggested that the dietary recommendation for iron should be raised to 14mg for vegetarian men and to 33mg for vegetarian women (2). This is because the vegetarian diet is rich in phytates – compounds found in whole grains, legumes, nuts and seeds – which inhibit iron absorption.
Meat eaters on the other hand tend to get much of their iron in the form of haem iron from meat, fish and poultry, which is better absorbed.
For this reason, vegetarians should be careful to optimise their iron intake. Eating iron-rich foods with a source of vitamin C can enhance iron absorption. Some food preparation techniques, such as soaking and sprouting beans, grains and seeds, can break down phytates, making iron more bioavailable. An iron supplement may also be a sensible measure to ensure optimum intake.
Another important consideration for vegetarians is zinc intake. Again, plant-derived foods that are rich in zinc are also high in phytic acid, an inhibitor of zinc absorption. For this reason, vegetarians may benefit from a raised zinc intake to ensure that a sufficient amount is absorbed. A good vegetarian multivitamin containing iron and zinc will help to guard against any insufficiency. Including zinc-rich foods such as yoghurt, cheese, tofu, beans, lentils, nuts and seeds in your diet is important.
Vitamin D deficiency is common in the UK, in both vegetarians and meat eaters. While some foods contain small amounts of vitamin D, the main source of this vitamin for vegetarians and meat eaters alike is sunlight.
Unfortunately, many of us in the UK do not get enough sun exposure throughout the year. For this reason, vitamin D supplementation is commonly recommended. Current UK recommendations are that babies, children, pregnant and breastfeeding women, elderly people and those who are confined indoors or cover up for cultural reasons should all supplement vitamin D.
An additional consideration for vegetarians is that many vitamin D supplements are sourced from animals. Some vitamin D supplements are sourced from fish oil. In addition, strict vegetarians often prefer to avoid supplements containing vitamin D3 which is made from sheep’s wool. Fortunately, alternative vitamin D supplements sourced from lichen provide well-absorbed vegan vitamin D3.
DHA: Essential Brain Food
Vegetarian sources of omega-3 include green leafy vegetables and flaxseeds. This type of omega-3 fat, ALA, is helpful for cardiovascular health.
Unfortunately, the vegetarian diet is very low in DHA, which is another type of omega-3 fat needed for optimal brain function. The main source of dietary DHA is oily fish and organ meats, though dairy and eggs also provide small amounts. A vegetarian diet with dairy and egg products only supplies around 20 mg/day of DHA (3), which is far below recommended levels.
Because of its role in brain function, DHA intake has been linked to improving both learning and memory. It is also implicated in the slowing of cognitive decline (4,5).
The simplest way for vegetarians to meet the recommended amount of DHA is to take a marine algae supplement. Omega-3 supplements made from algae are just as effective as fish oil supplements, and provide a simple and direct source of vegetarian DHA.
The Vegetarian Lifestyle
The advantages of a vegetarian diet are well studied. Vegetarians have been found to have lower blood pressure, a lower BMI and a lower risk of developing cardiovascular disease. Although some nutrients may be less available in a plant-based diet, being aware of these potential pitfalls can help to optimise your nutritional status while reaping the many benefits of a vegetarian lifestyle.
1. Davey G et al. (2003) EPIC-Oxford: lifestyle characteristics and nutrient intakes in a cohort of 33,883 meateaters and 31,546 non meat-eaters in the UK. Public Health Nutrition 6: 259–68.
2. Hunt J (2002) Moving toward a plant-based diet: are iron and zinc at risk? Nutrition Reviews 60 (5): 127–34.
3. 41. Sanders TA. DHA status of vegetarians. Prostaglandins Leukot Essent Fatty Acids. 2009 Aug-Sep;81(2-3):137-41.
4. 10. Su HM. Mechanisms of n-3 fatty acid-mediated development and maintenance of learning memory performance. J Nutr Biochem. 2010 May;21(5):364-73.
5. 28. Hashimoto M, Hossain S. Neuroprotective and ameliorative actions of polyunsaturated fatty acids against neuronal diseases: beneficial effect of docosahexaenoic acid on cognitive decline in Alzheimer’s disease. J Pharmacol Sci. 2011;116(2):150-62.