Add as bookmark

The Pitfalls of a Vegetarian Diet

by Penny Crowther(more info)

listed in vegetarianism, originally published in issue 85 - February 2003

Most vegetarianism-related research has found it to be a healthy way of eating. One Surrey University survey found that meat eaters visited their doctors twice as often and suffered from degenerative diseases ten years earlier than vegetarians.[1] However, a poorly thought out vegetarian diet can be disadvantageous as illustrated by two cases in my practice.

Case Histories


Nancy's lifestyle presented a particular challenge. As well as being a strict vegetarian she worked night shifts, which meant she had to eat at unusual times. A typical day's food intake would be toast with margarine for breakfast, a salad sandwich for lunch and a vegetable curry in the evening. She occasionally ate cheese, usually in pizzas or sandwiches. She was not eating sufficient protein.

Amongst the general population, lack of dietary protein is unusual. In fact, many westerners eat too much protein. But vegetarians who don't eat beans and pulses and get bored of eating cheese may be going short. Suggested protein intakes vary from 45-70g[2] depending on age, sex and biochemic individuality. 100g portions of seeds, Brazil nuts or butterbeans contain 27g, 16g and 19g of protein respectively. I find that people, particularly those who are of a highly-strung, nervous disposition with a tendency to crave sweet foods, do well on a slightly higher protein intake.

Vegetable protein is very advantageous because it is lower in saturated fats and contains more fibre than protein from animal sources.

However I explained to Nancy that if she was relying solely on vegetable protein she needed to be aware of the best way to combine foods to obtain the most comprehensive range of amino acids. Vegetables tend to be low in methionine, for example, whilst beans and lentils are rich in this amino acid. So combining beans or lentils with rice, or mixing millet with sesame seeds improves the overall quality of the protein. Nancy began to eat more protein rich soya foods as well as tofu. Adding soft (silken) tofu to soups or smoothies produces a creamy consistency. I suggested nuts and seeds as convenient protein rich snacks, which she could take to work. She agreed to eat a boiled egg with her breakfast toast.

My suggestions meant some extra effort in preparation, but Nancy was willing to try anything to achieve her aim of getting pregnant.

She had been trying for five years and had undergone two unsuccessful IVF treatments.

Nancy's problems conceiving and history of miscarriage, together with white spots on the nails, frequent colds, sugar cravings and poor appetite[3] led me to consider the possibility of zinc deficiency. Zinc is arguably one of the most important microminerals, essential for the function of eighty or more enzymes. Vegetarians are very vulnerable to zinc deficiency because the richest sources tend to be meat or seafood. As well as recommending zinc-rich foods such as pumpkin and sunflower seeds, I suggested a supplement which contained 36mg of zinc citrate in balance with a range of other minerals.

Nancy also took a supplement containing the fatty acid GLA, from evening primrose oil. Again vegetarians have to pay particular attention to their intake of essential fatty acids needed for a whole range of functions in the body such as creating healthy skin, supporting breast health, immune and lung function. Oily fish is a rich source of EFAs not available to vegetarians who would need to rely on nuts, seeds and oils such as flax oil. Fish oil has the advantage of containing the fatty acids DHA and EPA which are in a very readily absorbable form.

When Nancy returned to see me after four weeks she had not found it easy to make such radical alterations to her diet but had managed a 50% change. She had noticed that she had more energy and this inspired her to keep going and increase compliance. She became pregnant around two months after first starting her new diet.


Angela, aged 27, had been a strict vegetarian for eight years. She had an intolerance to nuts and seeds, which ruled out a valuable source of protein and essential fatty acids. She had very dry skin with patches of eczema which were quite severe in places and menstrual cramps two days before her period was due. Both of these symptoms can be signs of low EFAs. Lack of zinc is linked with skin problems.[4]

Angela also appeared to have some symptoms of B12 deficiency, for example numbness and tingling in certain parts of her body, low energy, a sore tongue and a history of anaemia. These can of course all be signs of other conditions so I recommended that Angela get her B12 levels checked. Vegans are particularly vulnerable to B12 deficiency,[5] since this vitamin is only found in animal foods or fortified foods such as plant milks, some breakfast cereals and soya foods. Algae such as seaweed, spirulina etc do not provide B12, contrary to some claims made by food manufacturers. The vegan society strongly advises that vegans take a supplement of 10mcg B12 daily to avoid deficiency. B12 also lowers levels of homocysteine, reducing the risk of stroke and pre-eclampsia in pregnancy.

Angela's diet did include healthy fibre-rich foods such as wholemeal bread and cereals, fruit and moderate amounts of vegetables. She ate some cheese but again her protein intake was low and she was in danger of not getting enough zinc because the rich vegetarian sources are seeds and nuts, which she was omitting. I recommended legumes, especially aduki beans, oats and wheatgerm, which all contain moderate amounts of this mineral. I advised Angela to avoid cheese for a period of two months since dairy intolerance is often a factor in eczema. This would take out a good source of calcium and zinc as well as protein from the diet, so I stressed the importance of having beans and grains daily. I recommended yoghurt of the live goat or sheep variety. The bacteria in live yoghurt are beneficial for the digestion and immune system. She found houmus a convenient protein food and rotated seeds and nuts on a five day basis to avoid intolerance. With the help of flower remedies to address emotional issues, Angela's skin was virtually clear within a few months.

As these cases show, provided the temptation to rely heavily on protein from dairy foods is avoided, a good vegetarian diet is a healthy way of eating. If not eating dairy foods, it is essential to include two daily serving of protein from tofu, nuts, beans, peas or lentils.


1. Dickerson JWT et al. Disease patterns in individuals with different eating patterns. Journal of Royal Soc of Health. 105: 191-194. 1985.
2. Crim M and Munro H. Protein. Present knowledge in nutrition: 9th ed. Nutrition Foundation: 49. New York. 1976.
3. National Research Council. Recommended dietary allowances: 9th ed. National Academy of Sciences. Washington DC.
4. Baer MT al. Nitrogen utilisation, enzyme activity, glucose tolerance and leucocyte chemotaxis in human experimental zinc depletion. Am Journal of Clinical Nutrition. 41: 1220-1235. 1985.

5. Gleeson M and Graves P. Complications of dietary deficiency of vitamin B12 in young Caucasians. Postgraduate Med Journal. 50: 462-464. 1974.


  1. No Article Comments available

Post Your Comments:

About Penny Crowther

Penny Crowther BANT CNHC qualified as a nutritional therapist in 1997 and has been in clinical practice ever since. She has seen several thousand clients over the years, at her practice in London and online. Penny now specializes in nutrition for women in their 40s and beyond, particularly around peri and post menopause. Mid Life for women can be a time when fluctuating hormones play havoc with your wellbeing. In the midst of all the publicity around HRT, it's easy to forget just how powerful diet and lifestyle changes can be when it comes to navigating the menopausal years.

Penny will guide and support you through specific changes to your diet, targeted to you specifically, in midlife. She provides practical, easy to follow menu plans with easy and delicious recipes. The food you eat affects every cell and system in your body. It optimizes how you look and feel, both mentally and physically.

To book an appointment view consultation options here >>

As well as being a regular columnist for Positive Health, Penny has written for Holland and Barrett, and contributed to articles for the Daily TelegraphThe Times Literary supplement, Pregnancy & Birth and Marie Claire. She has been featured in the Daily Express, Daily Mirror and on local radio.

Penny is a registered nutritional therapist with standards of training endorsed by BANT (British Association for Applied Nutrition and Nutritional Therapy) and CNHC. This includes completing 30 hours of continuing professional development, annually.

Penny’s approach to health is holistic, and takes into account emotional, mental and environmental factors as well as nutrition. She has trained in coaching and studied many complementary therapies before qualifying as a nutritionist, which provides a broad foundation of knowledge in her nutrition practice. Penny may be contacted on Tel: 07761 768 754;

top of the page