Sebastian Pole looks at the Ayurvedic perspective of how both the quality of food as well as the quality of digestion influence our health.
“The body is the outcome of food. Even so, disease is the outcome of food. The distinction between ease and disease arises on account of wholesome nutrition or the lack of it respectively.” – Charaka Samhita (an early Ayurvedic text from 1 BCE)
Ayurveda could be called the ‘science of digestion’. It believes that a faulty digestion is the cause of most diseases. Certainly, the majority of patients presenting in my clinic have some form of digestive disorder. However good your diet is, if your digestion is impaired then you cannot absorb the appropriate nutrients required for nourishment. This ultimately causes in the depletion of the entire system and results in disease. However, a good diet is essential too. In this article I want to look at the Ayurvedic perspective of how both the quality of food we eat as well as the quality of digestion influence our health and how by treating the ‘root’ cause of disease we can help our patients heal.
Current nutritional trends
Nutritive food protects health and prevents disease. It is as simple as that. It is estimated that at least 30% of all cancers are diet related and it is also known that 70% of these cancers are connected with typical diets that are high in animal fat, low in fruit, vegetables and fibre (1). Prostate, breast and colon cancer are frequently connected with diet. Why is this? Perhaps it is to do with dietary changes?
Since 1950 there has been a global reduction of calorific intake in the consumption of complex carbohydrates by 38% and an increase of 12% for meat and 46% for vegetable oils. In the same period in the UK there has been a fall in fresh vegetable consumption by 24% and in the EU and US there has been a 35% increase in sugar and refined starch consumption. In the USA 35% of all fruit and vegetables consumed are consumed as ‘french fries’! Our shift in nutritional habits over the last 60 years has evidently had a negative impact on society’s health as the same time period has seen cancer rates double and also sharp increases in heart disease, alzheimers, diabetes and other chronic degenerative diseases. Despite there being a surplus of food quantity there has been a decline in food quality to the extent that Type-B malnutrition is now prevalent in the industrialised world with up to 60% of hospital admissions displaying nutritional deficiencies (2,3,4).
An increase in nutrition received from meat is a good example of how more can be less. Well-cooked meat, especially barbequed meat contains aromatic amines, including 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (2, 3), more accessibly known as PhIP, which is associated with bowel, breast and prostate cancer in human cell line studies. The increase in meat consumption is directly correlated with an increased incidence of death from cancer, as seen by statistics showing New Zealand as having the highest meat consumption and the highest levels of colon cancer. Conversely, vegetarian diets are known to extend life and reduce degenerative diseases (see below) (6).
Other qualitative and quantitative nutritional factors are altering society’s health. Obesity has clear links with some forms of cancer as well as heart disease, diabetes, infertility and bone disorders (5). Low selenium levels are specifically implicated in prostate cancer (6). In contrast to this, the increased use of protective oils containing Omega 3 and Omega 6 fatty acids is linked to a reduced rate of cancers. Certain plant nutrients, known as ‘phytochemicals’, such as lycopene (the red pigment in tomatoes), carotenoids (the orange in carrots) and flavonoids (found in onion) have proven to be protective against prostate cancer. Studies have shown that increasing essential nutrients can give essential protection against degenerative diseases such as Alzheimer’s, arthritis, coronary heart disease, macular degeneration, depression and cancer. Changing one’s diet to a health promoting diet has been shown to reactivate certain genes known as Tumour Suppressor Genes, especially p53, that can keep tumours in check and force their cells to die (7, 8, 9,10,11).
Interestingly, but not surprisingly, organically grown food has been shown to have higher levels of nutrients and anti-oxidants than non-organic products. Studies comparing the nutritional value of organically grown and conventionally grown fruits, vegetables, and grains conclude there are significantly more nutrients in organic crops. These include: 27% more vitamin C, 21.1% more iron, 29.3% more magnesium, and 13.6% more phosphorus, 70% higher omega 3 content and certain vegetables have been shown to have 100% higher levels of cell protective flavonoids. In addition, organic products have 15.1% less toxic nitrates than their conventional counterparts. Interestingly, the government recommended five daily servings of vegetables (lettuce, spinach, carrots, potatoes and cabbage) provided the recommended daily intake of vitamin C for men and women when they are organically grown but their non-organic counterparts did not. Eating organic affects the amount of flavonoids, quercetin, and anti-oxidants that are protecting and nourishing you. You are also avoiding exposure to excessive levels of immune damaging pesticides and organophosphates (12, 13, 14, 15).
Ayurvedic nutrition
“It is obvious that the body tissues cannot be nourished and developed when food is not properly digested by the digestive fire.” – Charaka Samhita
Ayurvedic Nutrition is a deep science. It is not a one-diet-fits-all approach. And that is the beauty of Ayurveda, the traditional medical system of India. It recommends what is right for you. It also reminds us that what is right for us one day may not be right for us the next. It teaches a deep awareness and connection with our digestive system. If you practice Ayurveda, you begin to fall in love with your belly…’if music be the food of love, play on!’ The negative impact that a poor diet can have on our health, as we have seen above, shows that there has never been such a need for some salient nutritional advice. Ayurveda can help add to this nutritional advice.
Ayurveda has a theory that anything can sometimes be a food, sometimes be a medicine or sometimes be a poison depending on ‘who’ is eating, ‘what’ is eaten, and ‘how much’ is eaten. For example, fresh ginger root is delicious in cooking as a food to flavour and help digestion. It is a stimulating medicine that can help clear a cold and induce a sweat when taken as a strong hot tea. However, if too much is taken it can make you sick causing acidity and vomiting, hence acting as a poison in the wrong circumstances. This refers to Ayurveda’s focus on the ‘quality’ of what we eat as well as the ‘quantitative’ nature of the food. So, there is no strict ‘Ayurvedic diet’ per se, only sage recommendations to help you find the tastiest and healthiest diet for your personal optimum health.
Eating is considered to be the most important activity that can affect health. Whilst eating is an essential habit, and for some an addiction, it can be empowering to transform your eating habits to only include healthy foods that are rejuvenating and life-giving. This is a healthy habit. Whilst herbal remedies, massage, exercise and spiritual practice can balance and repair health it is a ‘good’ diet that gives us an every day opportunity to take control of our health. We are stuck with our genes, family and climate but we can change our diet; when it comes to what we put in our bodies, we are in charge.
Generally speaking, Ayurveda considers that the most beneficial foods are rice, wheat, barley, mung beans, asparagus, grapes, pomegranates, ginger, ghee, milk and honey. These are all tonics to the tissues and digestion. It also generally recommends that it is best to avoid habitual use of heavy meats, cheeses, yoghurt, refined salt, processed foods, refined sugar, coffee, tomatoes, bananas, citrus fruits and black lentils. These can create stagnation and undigested toxins, the scourge of all of our health problems.
Of course, many people have now become ‘intolerant’ to wheat and dairy. In my experience this is a result of a combination of a weak digestive fire with ‘unnatural’ foods. For example, I call bread ‘unnatural’ as modern baking techniques require that it is leavened with synthetic yeast in a couple of hours. For a proper healthful fermentation bread should leaven over an 8 hour period using a natural sour-dough fermentation; this neutralises phytic acid which helps make the nutrients in the bran more bio-available and does not block calcium and iron absorption; it creates gut-healthful lactobacillus bacteria (as opposed to Candida albicans-promoting synthetic yeast) which assist with assimilation and the health of the digestive tract and also increasing the B vitamin content of bread. Add a powerful digestive system and you get optimum absorption of the best quality food. Commercially yeasted bread causes bloating, gas and aggravates the nutritional state of the tissues and the micro-flora in the digestive tract. No wonder so many people are intolerant to it. Ayurveda says that yeast is a negative ingredient that aggravates every constitution.
This sort of understanding pervades Ayurveda. After all it is literally translated as ‘the Science if Life’. It has detailed practical theory covering all aspects of living a positive and health generating life-style. It literally gives you the clear information to live healthily and fulfill your potential. I have seen its innate wisdom empower and transform hundreds of people’s lives.
I clearly remember one 48 year old woman with ulcerative colitis who had been on various courses of steroids that helped whilst she remained on the medication but all the symptoms flared when she came off the drugs. Minimal dietary advice had been given by her primary carer. She ate a typical British diet including coffee, cereals, milk, sandwiches, frequent meat, low vegetables and occasional alcohol. Through simply applying some of the principles mentioned in this article to strengthen her digestive fire, adjust her diet to a more wholegrain (rice, quinoa, barley), high vegetable, low sugar diet along with some herbs to clear intestinal inflammation (Triphala, Neem, Turmeric) she has remained almost symptom free and has not needed steroids for over 3 years. It was by allowing her digestive energy to flourish that her health was able to heal.
Now let’s look at how we can all look after our digestive altar. Remember that digesting your food properly depends on:
- A strong digestive fire called agni in Ayurveda
- Eating appropriate foods in the correct quantity and of the correct quality
- Healthy food combining based on Ayurvedic principles
The metaphor of fire
The Indian Vedic culture revered agni or fire, which gave them light, warmth and cooked their food. Agnideva is the Fire god who acts as a messenger between the mortal world and the heavens. In Vedic rituals humans offer oblations (the act of offering something such as worship or thanks to a deity) to the sacred fire. The fire takes a portion for himself and then vaporises the rest for the benefit of the gods. The gods imbibe this nutritious fragrance and in return give life-giving waters and favourable environmental conditions from which crops flourish and humans can feed themselves. This benevolent cycle continues as long as both parties are happy.
It is a metaphor of our own digestive system. We eat and ‘offer’ food into the fire of our bellies. Agni digests this food and the control centres in the brain are nourished by these fragrant nutritional ‘vapours’. This nourishment feeds the nervous impulses, which release enzymes and hormones. This stimulates systemic metabolic activity so that the whole body-mind complex functions efficiently. Hence eating is seen as a sacred act that should be given its full attention away from stress, disturbance and distractions.
Agni is seen as the metaphor for all metabolic functions in the body. It includes the digestive function, sense perception, cellular metabolism and mental assimilation. The agni’s ability to transform also gives it a pivotal role in absorbing life’s experiences as it works through the heart and mind to help process emotional and cognitive experiences. It is said to carry the inherent cosmic intelligence into our tissues.
Agni is involved in many functions:
- absorption
- assimilation
- metabolism
- digestion
- perception
- taste
- touch
- hearing
- vitality
- clarity
- alertness
- regular appetite
- it gives immunity, a sparkle in the eyes and lustre to the whole body.
The qualities of digestive agni are:
- hot
- light
- sharp-penetrating
- pungent
- luminous-clear
When it is balanced it causes emotions that are beneficial to health: courage, happiness, cheerfulness, lucidity, optimism, enthusiasm and intelligence. It also provides energy, vitality and a system able to maintain homeostasis.
When it is out of balance it causes emotions that are destructive to health: fear, anger, confusion, idiocy, depression. This also leads to low energy, congestion and an accumulation of wastes. Modern research also shows that gut health is closely linked to energy levels, mental clarity and wellbeing.
The four types of digestion
There are four types of digestive fire that generally categorise people’s digestive tendencies. Which one are you?
Ayurveda recommends specific foods for each type of digestive fire.
1. Irregular digestion
This is an irregular appetite and digestive system with signs of variable hunger, bloating, indigestion, intestinal cramps, constipation, dry stools, gurgling and gas. It is common in nervous people (known as vata types in Ayurveda).
Using spices that have a carminative, warming and relaxing action can be useful. Ayurveda has a formula called Asafoetida Plus (made from asafoetida, fennel, cumin, nigella seed, ginger, black pepper) taken 30 minutes before meals can help balance this erratic type of digestive system.
2. Intense digestion
Intense hunger but with poor digestion is a sign of a hyperactive digestion. There may also be symptoms of thirst, parched mouth, dry throat, loose stool and a burning sensation in intestines are common concurrent symptoms. It is more common in ‘fiery’ people known as pitta types in Ayurveda.
Using herbs that can dilute the acidity in the stomach can help. Amla and Peppermint formula mixes certain bitter and cooling herbs to help balance this intensity of pitta in the digestive system.
3. Weak digestion
Weak hunger is a sign of low metabolism and sluggishness. These types of people also commonly have slow digestion, heaviness after eating a meal, sluggish bowels, bulky stool, feeling cold, sweet cravings and they crave stimulants. It is more common in kapha types of people in Ayurveda.
Stimulating spices such as in the formula Trikatu (Ginger, black pepper and long pepper) before a meal it can help alleviate this tendency and works a bit like proteolytic enzymes.
4. Balanced digestion
Balanced hunger and digestion; food is digested within 4 hours with no excess craving or lack of interest in food. These people can just use Ayurveda’s premium digestive regulator Triphala to help maintain a healthy digestive system.
If you really know your digestive system and how it reacts to the different challenges of your diet and the day then you can understand how to live right for your own needs. It is the best way to perfect health.
In fact, the simplest and best suggestion of any diet is just to follow your hunger. Only eat when you are hungry. This way your digestive fire will express its own innate wisdom and let you know when it is time to eat, when it is time to drink and when it is time to rest. It really is that simple. Learning to really understand true hunger gives you an insight into the deeper workings of your self, your attachments to food, how you are nurtured by what you eat and how you care for yourself by what you eat. A beautiful way to love yourself is by giving yourself the food you really need. We all love a bit of chocolate cake and so you should enjoy it. It tastes great and chocolate is a wonderful mood enhancing food. Just make sure that the remaining 99% of the time you are giving yourself what you truly need.
Specific diets
Ayurvedic food combinations
It is not just the food you eat that affects digestion but how you put them together that affects your health. When it comes to food, not everything is equal. Foods have different tastes, heating or cooling qualities, moistening or drying qualities and building or cleansing effects. According to Ayurveda, if foods with different energetic qualities are combined then they can cause incompatibilities which can upset digestion leading to indigestion, gas, diarrhoea, constipation and ama. This ultimately leads to food intolerances and other health imbalances such as sinus congestion, lowered immunity and skin problems.
Ayurveda has these lovely balancing tricks. Its not a puritanical system dictating what is ‘good’ and what is ‘bad’. It is an experiential system based on creating what is right for you. If we can agree that foods have effects: e.g. beans are good for your heart via their plant sterol cholesterol lowering function but beans are also hard to digest, then we can agree that foods can have opposing effects. These can be balanced with careful food combining and Ayurveda recommends cumin, coriander and asafoetida to help with the digestive disrupting side effects of beans.
Incompatible foods can cause problems because they digest at different speeds and can cause fermentation or excessive mucus.
Overview of foot compatibilities
| Food type | Compatible with | Exceptions |
|---|---|---|
| Fruit | Other food. It should be eaten at least 2 hours away from other foods | Dates together with milk are ok. |
| Milk | Bananas, bread, yoghurt, fish, meat, melons, cherries, sour foods | |
| Yoghurt | Fruit, milk, meat, solanacea family, eggs, fish | |
| Eggs | Milk, fruit, yoghurt, cheese, fish, meat | |
| Grains | Fruit | |
| Beans | Fruit, cheese, eggs, yoghurt, milk, fish, meat | |
| Lemons | Milk, yoghurt, tomatoes, cucumbers | |
| Honey | Ghee (by weight) 1tsp honey = 3tsp ghee Honey should not be heated | Adding honey to a warm drink is ok. |
| Radishes | Bananas, raisins, milk | |
| Melons | Any other food | |
| Raw food | Cooked food | |
| Fresh food | Leftovers |
Incompatible foods and antidotes for balance
Ayurvedic digestive tips
- Start each meal with chutney of ginger, lime and a pinch of rock salt (or just chew a piece of fresh ginger)
- Eat warm food that is freshly cooked (Ayurveda promotes the use of warm food as this is easier to digest)
- Avoid processed, cold-refrigerated and stale foods
- Chew properly to ensure that digestive enzymes get to work in the mouth
- Sip warm water with each meal but do not drink lots of fluids within an hour after finishing your food as this can weaken the digestive fire
- Avoid iced water
- Eat in peace
- Do not eat when stressed, angry or depressed
- Eat with awareness; be aware of how your digestive fire is every day and eat appropriately for your constitution.
- Stop eating when you are half full of food and a quarter full of liquid, leaving a quarter of your digestive capacity free for life-giving prana to circulate and help digestion
- Eat your food with respect for nature and the gift of nutritious food she has bestowed upon you. Give thanks to the creator of your meal
- Eat sitting down. Do not eat standing up. (16)
- Have a short walk after each meal, however do not take excessive exercise, sleep or have seat for an hour after eating
- Do not eat a heavy meal at night and leave at least two hours from eating before going to bed
Vegetarianism
Although Indian culture is often associated with vegetarianism, Ayurveda is not wholly vegetarian. Ayurveda is a science in pursuit of health. It is not a moralistic system, although morality does creep into its practices. If someone’s health can benefit from the properties of eating some animal meat, then this is recommended. For example, this might happen if someone is extremely weak after an illness. Ayurveda would understand that there is some karma, or effect, from using animal products, but argues that the health of the individual is paramount. That being said it does recommend a primarily vegetarian diet that is easy to digest. In accordance with Ayurvedic principles it would also encourage an awareness of one’s actions and there is little doubt that the massive impact of the meat industry on the environment, economy and health of society would influence the opinion of the original propounders of Ayurveda.
Environmentally vegetarianism is more sustainable. One quarter of the earth’s surface is now pastureland to support livestock! ¾ of all grains and beans grown in the US are destined for animal feed (17).
Economically vegetarianism costs the world less. As demand grows, intensification practices rush to support the market. This means that many animals are kept in conditions that increase the risk of disease, requiring persistent treatment with anti-biotics. Of all food poisoning incidents in the UK 95% are due to animal products.
Vegetarians have been shown to have longer and healthier lives than meat eaters as well as less cancer, obesity and heart disease. Interestingly, New Zealand has the highest per capita levels of meat consumption and the highest levels of bowel cancer in the world. Globally calorific intake from meat has increased by 36% since 1950 and vegetable consumption has dropped by 24% in the same time period in the UK. The shift in our nutritional habits is clearly having a negative impact on society’s health as the WHO state that 30% of all cancers are diet related and that 70% of all cancers are connected with typical diets that are high in animal fat, low in fruit, vegetables and fibre (18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31 32, 33, 34).
Whatever your dietary predilection Ayurveda would recommend eating with awareness.
Recipes
The following are tried and tested delicious recipes.
Kicharee
Serves 2-3
Ingredients and preparation
- 1/3 cup or 100 gms split mung dal, 2/3 cup 200gms or basmati rice (or other grain) simmered in 3-4 cups of water (a ratio of 1:3 or 1:4).
- Add 1/4 tsp organic turmeric, ginger, roasted cumin and coriander.
- Add seasonal vegetables: spinach, peas, carrots or seaweeds and simmer on low heat in the lentil-rice mix for 30-40 minutes for an all round healing, healthy and agni enkindling meal.
- It’s best not to stir this once all the ingredients are in as it can go ‘mushy’. Mix it once, put a lid on, turn the heat down and enjoy the fragrant aromas filling your house. Leave it to sit for 10 minutes at the end.
- Add a teaspoon of ghee or hempseed oil at the end.
- Salt and pepper to taste.
Other kicharee tips
- Whilst fasting on kicharee it can be useful to sip hot drinks; try spicy teas of black pepper, cinnamon and cardamom to burn ama, clear toxins and relax your contracting stomach.
- For a ‘medicinal’ meal add powders of shatavari, bala, ashwagandha, pippali, amla, almonds, walnuts; approx 1 tsp/person.
- Try adding fresh rose, marigold, borage petals.
- Try adding rose petal jam or rose water.
Rice pudding elixir
Ingredients
- 100g rice pudding rice (You can also try with black or red rice)
- 1 litre of cow’s, almond or rice milk (option of more)
- 3 tbs almond powder
- 7 strands of saffron
- 5 cardamom pods
- Rose Jam
- Ghee or honey, optional
Method
- Place the rice in a heavy pan and add the milk. Bring to boil and simmer for 1 hour.
- Add the almond powder. Add more milk as desired. (coconut milk is an interesting change)
- Soak the strands of saffron in a tablespoon of milk for 10 minutes to extract its golden pigment and then add to rice pudding. Add cardamom and rose jam. Serve and add ghee or honey as desired.
- You can also add grated carrots or beetroots to this recipe for a colourful and nourishing variation.
- This is a very nourishing food for reducing vata and pitta, strengthening the tissues and building reproductive tissues.
Hot milk recipe
Serves 1
Ingredients
- 1 cup of cow’s, almond or rice milk
- 2 tsp organic almond powder
- 2 cardamom pods
- 5 strands saffron
- Pinch of nutmeg
Method
- Put all the ingredients into a pan and heat until boiling.
- Allow to cool and add 1 tsp honey (optional). Take with 1-2gs or caps of organic ashwagandha at night to help nourish the nervous system, reproductive system and it helps you sleep.
I hope that some of this wisdom that Ayurveda offers you for dietary balance helps you towards healthier and more delicious eating.
References
- WHO, World Cancer Report 2003.
- Gallagher-Allred CR, Voss AC, Finn SC, McCamish MA. Malnutrition and clinical outcomes: the case for medical nutrition therapy. J Am Diet Assoc 1996 Apr;96(4):361-6, 369.
- Bistrian BR, Blackburn GL, Vitale J, Cochran D, Naylor J. .Prevalence of malnutrition in general medical patients. JAMA 1976 Apr 12;235(15):1567-70.
- Naber TH, et al. Prevalence of malnutrition in nonsurgical hospitalized patients and its association with disease complications. Am J Clin Nutr 1997 Nov;66(5):1232-9.
- Cerhan JR, Torer JC, Lynch CF, et al. Association of smoking, body mass, and physical activity with risk of prostate cancer in the Iowa 65+ Rural Health Study (United States). Cancer Causes and Control 1997; 8(2):229–238.
- Cui Z, Liu D, Liu C, Liu G. Serum selenium levels and prostate cancer risk. Medicine (Baltimore). 2017;96(5):e5944. doi:10.1097/md.0000000000005944
- Giovanucci E., et al ‘95. “Intake of carotenoids and retinal in relation to risk of prostate cancer.” Journal of National Cancer Institute; 87:1767–76.
- Lewin M, Bailey N, Bandaletova T, Bowman R, Cross AJ, Pollock J, Shuker D, Li, H, et al. A prospective study of plasma selenium levels and prostate cancer risk. Journal of the National Cancer Institute, vol. 96, May 5, 2004, pp. 696-703.
- Taylor, PR, et al. Science peels the onion of selenium effects on prostate carcinogenesis. Journal of the National Cancer Institute, Vol. 96, May 5, 2004, pp. 645-47 (editorial).
- Drewnowski, A. Fat and Sugar: An Economic Analysis J. Nutr. 133:838S-840S, March 2003.
- Drewnowski, A. & Popkin, B. M. (1997) Dietary fats and the nutrition transition: new trends in the global diet. Nutr. Rev. 55:31-43
- Worthington V, Nutritional Quality of Organic Versus Conventional Fruits, Vegetables, and Grains, The Journal of Alternative and Complementary Medicine, Vol. 7, No. 2, 2001 (pp. 161-173).
- Heaton , Organic Farming, Food Quality and Human Health: A review of the evidence, The Soil Association, United Kingdom, 2001.
- Grinder-Pedersen, Salka E. Rasmussen, Susanne Bügel, Lars V. Jrgensen, Lars O. Dragsted, Vagn Gundersen, and Brittmarie Sandström, Effect of Diets Based on Foods from Conventional versus Organic Production on Intake and Excretion of Flavonoids and Markers of Antioxidative Defense in Humans, J. Agric. Food Chem., 51 (19), 5671 -5676, 2003.
- Zheng T, Zahm SH, Cantor KP, Weisenburger DD, Zhang Y, Blair A. (2001) Agricultural exposure to carbamate pesticides and risk of non-Hodgkin lymphoma.J Occup Environ Med. 43(7):641-9.
- Pole, S, Ayurvedic medicine, the principles of traditional practice, Elsevier, 2006.
- Vesterby, Marlow and Krupa, Kenneth S. 2001 Major Uses of Land in the United States, 1997 Statistical Bulletin No. (SB973) September 2001 LEAD digital library: Livestock’s long shadow – Environmental issues and options.
- Bingham SA. Red meat enhances the colonic formation of the DNA adduct O6-carboxymethyl guanine: implications for colorectal cancer risk. Cancer Res. 2006 Feb 1;66(3):1859-65.
- Burr, M & Butland, B. (1988) Heart disease in British vegetarians. Am Jnl Clinical Nutrition v.48 p.830-2.
- Claude-Chang, J et al. (1992) Mortality pattern of German vegetarians after 11 years of follow-up. Epidemiology v.3 (5) p.395-401.
- Cummings, J & Bingham, S. (1998) Diet and the Prevention of Cancer BMJ v.317 p.1636-1640.
- Doll, R. (1990) Symposium on diet and cancer. Proc of the Nutrition Society v.49 p.119-31.
- Dwyer, J T. (1988) Health aspects of vegetarian diets. Am Jnl Clinical Nutrition v.48 p.712-38.
- Gale, Catharine R; Ian J Deary, Ingrid Schoon, G David Batty, G David Batty (2006-12-15). “IQ in childhood and vegetarianism in adulthood: 1970 British cohort study”. British Medical Journal 333 (7581).
- Galeone C, Pelucchi C, Levi F, et al. Onion and garlic use and human cancer. Am J Clin Nutr 2006;84: 1027-32.
- Margetts, B M et al. (1986) Vegetarian diet in mild hypertension: a randomised controlled trial. BMJ v.293 p.1468-71.
- Marsh, A G et al. (1988) Vegetarian lifestyle and bone mineral density. Am Jnl Clinical Nutrition v.48 (3) p.837-41.
- Sellmeyer, D E et al. (2001) A high ratio of dietary animal to vegetable protein increases the rate of bone loss and the risk of fracture in postmenopausal women. Am J Clin Nutr 2001; 73:118-22.
- Spencer, Colin: The Heretic’s Feast. A History of Vegetarianism, London: Fourth Estate 1993.
- Thorogood, M et al. (1994) Risk from death from cancer and ischaemic heart disease in meat and non meat-eaters. BMJ v.308 p.1667-1671.
- Thorogood, M et al. (1987) Plasma lipids and lipoprotein cholesterol in people with different diets in Britain.
BMJ v.295 p.351-3. - Walters, K and Portmess, L, Religious Vegetarianism From Hesiod to the Dalai Lama, Albany 2001.
- Willett, W C et al. (1990) Relation of meat, fat and fibre intake to the risk of colon cancer in a prospective study among women. New England Jnl of Medicine v.323 p.1664-72.
- World Health Organisation (1990). Diet, nutrition and the prevention of chronic diseases. WHO, Geneva.
