The evidence that vegan and vegetarian diets come up short on specific nutrients

My attention was recently caught by research carried out in Kenya which shows that supplementing children’s diets with meat assisted their growth, and also led to improvements in their performance in problem-solving and intelligence tests. As a result of this and other research, the lead researcher of this study has described brining up children as strict vegans as unethical�. Personally, I think this sort of judgement is a bit strong, but this recent study does I think highlight the fact that vegan, and also vegetarian, diets tend to be low in specific nutrients required for healthy growth, development and general well-being. I thought I’d look this week at the sort of nutrients such diets tend to be low in, and what can be done to beef them up.

Protein: in years gone by, dieticians would stress the importance of protein for proper growth and development in children. However, a general trend towards emphasising the value of carbohydrates in kids’ diets has seen protein slip off the menu of late. Recently, Danish researchers decided to give the role of protein in childhood growth another look. The results of this study, published in the American Journal of Clinical Nutrition, showed that higher levels of protein in the diet were associated with increased height and weight in 10-year-old kids. There was no association found between protein intake and body fat percentage. This suggests the increased weight associated with a good intake of protein was not the result of excess fat, but due to an increase in the amount of non-fatty body tissues such as muscle and bone. This study confirms that adequate protein is important for optimal growth in children.

Protein-rich foods to include in their diet include meat, fish, eggs, yoghurt, nuts, beans and lentils.

Protein is composed of molecules known as amino acids. Amino acids that come from protein in the diet are used as building blocks in the manufacture of many structures and tissues in the body including bone and muscle. There are 22 amino acids, most of which can be made in the body and therefore do not, strictly speaking, need to be provided in the diet. However, children are unable to make 10 amino acids, and their presence in the diet is therefore crucial to optimum health. These are referred to as the essential amino acids.

Meat and fish are very good sources of protein, as are eggs and dairy products such as milk, cheese and yoghurt. Some non-animal foods, such as beans, peas and nuts and seeds, are also good sources of protein. Some foods provide a good balance of essential amino acids and are generally regarded as superior sources of protein than those foods that may be lacking in one or more essential amino acids. In general, animal-derived proteins are regarded as more ‘complete’ in terms of their component amino acids than vegetables sources of protein. For this reason, those who do not eat animal foods generally do well to eat a broad range of protein-containing foods including beans, pulses, nuts, seeds and perhaps soya based products (e.g. soya milk and tofu) too.

In addition to the issue with protein, vegan diets tend to be low in specific nutrients including vitamin B12, vitamin B2, calcium, iron, zinc and iodine. Even a vegetarian diet may be low in some of these nutrients, notably iron, vitamin B12 and iodine. Foods the eating of which can help counter these deficiencies include green leafy vegetables (calcium), calcium fortified non-dairy milks such as soya and rice milk, nori seaweed (vitamin B2 and iodine), nuts (calcium) and dark chocolate (calcium). For vegetarians, eggs offer good quality protein, in addition to some iron and vitamin B12. Vegans are very prone indeed to B12 deficiency, and are generally recommended to supplement with this nutrient.

While I am a great believer in the health giving properties of a healthy diet, it can nonetheless be hard for vegetarians and vegans to cover their nutritional bases.

6 Responses to The evidence that vegan and vegetarian diets come up short on specific nutrients

  1. SR 11 March 2008 at 7:48 am #

    Just thought I’d say that is all nonsense. Vegan or vegetarian diets are far healtheir than omnivores, and deficiencies are just as common in those who eat meat.

  2. Dr John Briffa 11 March 2008 at 7:53 am #

    SR – have you got any evidence that vegan or vegetarian diets are far healthier than omnivorous diets, or are you simply expressing your personal opinion?

  3. SR 14 March 2008 at 2:47 am #

    I am vegan and I have no deficiencies whatsoever. I am nit a health nut, nor do I spend alot of time planning meals or taking supplements. I eat a normal vegan diet without using a calculator to tot up all my vitamins and minerals. I am never ill, and yet my omnivorous friends always seem to be coming down with some illness, even the ones who eat healthily but invlude animal products. If you were to do a little research ( provides information for both laymen and scientifically minded people) you would find that vegans are the healthiest people in the world. The man who invented the word vegan died a few years ago at the age of 97. It really does annoy me that people state these things about vegetarian diets without investigating the facts or simply accepting blindly and without consideration the biased research of some companies. I recommend The China Study by T. Colin Campbell (the largest nutritional study ever performed) which explains veganism’s healthy appeal. He states that ‘every man, woman and child should be vegan’ if they care about their health.

  4. Dr John Briffa 14 March 2008 at 7:47 am #

    The support for the vegan diet you provide about the health status of you and your omnivorous friends is anecdote (not science). As for the much-trumpeted ‘China study’, can I refer you to this link below? It is, I think, I thorough dismantling of this ‘study’ and the conclusions drawn from it. Scroll down to the part that is entitled:
    The China Study: More Vegan Nonsense!

  5. Janet 3 April 2009 at 5:24 am #

    Funny how many vegans are nature lovers, yet thier diet seems to go against nature. Humans are omnivores! Check any science textbook.

  6. Janet 3 April 2009 at 5:27 am #

    Hey, SR: I can say that I know a man who is 101, and has eaten meat every day of his life. I know a 98 year old woman who smokes and is overweight. This does not mean that smoking and being overweight caused her to live long. Citing one example proves nothing.

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