Proteins

Proteins are large molecules made from smaller units called amino acids. There are twenty amino acids commonly found in both plant and animal proteins. There are generally considered to be eight amino acids that the body cannot make itself which need to be obtained from the food we eat. These are isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan and valine. Infants additionally need food sources of histidine and possibly taurine. Proteins are necessary for maintaining tissues and for sustaining growth. They are also used to make hormones and other physiologically active substances.

Protein Requirements [1] Experts are still not entirely sure how much protein we need and estimates have been revised often in recent years. The national and international organisations which advise on nutrient requirements suggest standards which are calculated to meet or exceed the requirements of practically everyone in the population. They take into account individual variation and so the levels have a wide inbuilt safety margin. The recommendations below are based on the complete digestibility of milk or egg protein. Since protein from plant sources may be slightly less digestible, the UK's Department of Health recommends that vegetarians and vegans multiply the above figures by a factor of 1.1. The UK Reference Nutrient Intakes (RNI*) for protein are as follows: Type of person Infants/Children 0-12 months 1-3 yrs 4-10 yrs Boys 11-14 yrs 15-18 yrs Girls 11-14 yrs 15-18yrs Men 19-50 yrs 50+ yrs Women 19-50 yrs 50 + yrs During pregnancy

Amounts Required (g/day) 12.5-14.9 14.50 19.7-28.3 42.1 55.2 41.2 45 55.5 53.3 45 46.5 extra 6g/day

Breast feeding 0-6mths extra 11g/day Breast feeding 6+ mths extra 8g/day •

The RNI is a daily amount that is enough or more than enough for 97% of people. The RNI is similar to the Recommended Daily Amount used previously in the UK.

The US Recommended Dietary Allowances introduced in 1989 are similar to the UK values.

Vegan Sources of Protein The foods which commonly supply the most protein in a vegan diet are pulses (peas, beans, lentils, soya products), grains (wheat, oats, rice, barley, buckwheat, millet, pasta, bread), nuts (brazils, hazels, almonds, cashews) and seeds (sunflower, pumpkin, sesame). Examples of amounts of foods providing 10g of protein Type of food Soya flour 24 Peanuts 39 Pumpkin seeds 41 Almonds 47 Brazil Nuts 50 Sunflower seeds 51 Sesame seeds 55 Hazel Nuts 71 Wholemeal bread 95 Whole lentils dried 114 & boiled Chickpeas dried & 119 boiled Kidney beans dried 119 & boiled Wholemeal 213 spaghetti boiled Brown rice boiled 385

Quantity providing 10g protein (g)

Are Plant Proteins Second Class Citizens?

No, certainly not! Nutritionists once believed that plant proteins were of a poorer quality than animal proteins. And even now plant proteins are sometimes called 'second class' proteins whilst animal proteins are elevated to the 'first class' department. This belief centred on early research on the poor laboratory rat which showed that giving extra amino acids of weanling rats reared on a plant-protein diet improved their growth. The same was assumed to be true for humans. However, the parameters of the experiments were set in such a way that differences in the quality of plant and animal proteins were exaggerated. Also, rats and humans have different nutritional requirements, since weanling rats grow at a much faster rate, relatively, than human infants and therefore need more protein. A comparison of rat and human milk makes the difference quite clear: protein comprises only 7% of the calorie content of human milk, while rat milk contains 20% protein. If weanling rats were fed only human milk, they would not thrive. These tests over-estimated the value of some animal proteins while under-estimating the value of some vegetable proteins and The World Health Organisation has now abandoned this inadequate method of assessing the value of proteins to the human body.

Protein Combining - Is It Necessary? No, it really isn't necessary! Research on laboratory rats also led to the misleading theory of protein combining. [2] Protein combining has unfortunately gained momentum over the years. It was based on the idea that complementary protein foods with different limiting amino acids, such as beans and grains, should be eaten at each meal in order to enhance the availability of amino acids. Proteins in foods have a distinctive pattern, being higher in some amino acids and lower in others. For many years the quality of a protein reflected its amino acid pattern and was measured against the protein in a hen's egg which counted as 100%. By this method, in each protein the amino acid furthest below the standard reference is known as the limiting amino acid. This is not necessarily the one present in the lowest absolute amount but the one present in the lowest proportion compared to protein in a hen's egg! In most grains and seeds, the limiting amino acid is lysine, while in most pulses it is methionine. Tryptophan is the limiting amino acid in corn (maize), and in beef it is methionine. Although each food has a limiting amino acid, most foods have all amino acids in adequate amounts for human health. Even vegetarians are sometimes advised to combine vegetable proteins with dairy foods. This advice is now very old fashioned. Protein combining may reduce the amount of protein required to keep the body in positive protein balance but several human studies have indicated that this is neither necessary nor even always the case. Diets based solely on plant foods easily supply the recommended amounts of all the indispensable amino acids, and protein combining at each meal is unnecessary. Soya protein is actually equivalent in biological value to animal protein.

Protein - Too Much of a Good Thing?

Studies show that vegan diets provide the ideal amounts of protein recommended by the World Health Organisation and by the UK's Department of Health. On the other hand, many omnivores eat more protein than guidelines recommend and this may have disadvantages for their health. Excessive protein consumption may be associated with health risks. Kidney function can be compromised by too much protein in older people and in patients with kidney disease; also, a high protein intake may adversely affect calcium balance and contribute to mineral loss from bone. The Office of Population Censuses and Surveys 1990 survey of British adults [3] showed that average protein intakes are 84g/day for men and 64g/day for women which are higher than recommended, Different types of dietary protein may have differing effects on cholesterol and fats in the bloodstream. Greater hormonal responses resulted in a meal derived from casein (milk) than from soya beans. This suggests that milk protein leads to higher levels of cholesterol and fats in the blood. These, in turn, are risk factors for coronary heart disease. A survey of 620 women in Singapore revealed that, among pre-menopausal women, those who regularly ate soya protein and soya products in general had about half the normal risk of developing breast cancer. In contrast, the consumption of red meat and animal protein was linked with an increased risk of breast cancer in pre-menopausal women. Diets rich in meat protein lead to more uric acid in the urine, and a general increase in urine acidity. because of the acidity, the uric acid does not easily dissolve and can form into kidney stones.

Is there Enough Protein for Growing Children? Children's over-riding nutritional need is for energy rather than protein per se. As long as children's energy needs are being met they will thrive on a diet in which protein is available from a mixture of plant foods. Infants and children reared on a varied vegan diet obtain adequate protein and energy, and are healthy and grow normally. Although they tend to be of lighter build than omnivore children they are within the normal ranges for height and weight. Regular consumption of suitably-prepared high-energy foods, such as grains, pulses and nuts, with smaller amounts of bulky, less energy-dense fruits and vegetables, will ensure a satisfactory intake of protein and energy. There have been only two recent reports of protein and/or Calorie malnutrition in infants reared by vegan parents on a vegan diet, and these were due to over-dilution or inadequate variety of weaning foods. Other published cases of protein and energy deficiency in infants given alternative diets involved restrictive macrobiotic or fruitarian regimes, or dietary limitations imposed by non-vegan parents for perceived health reasons Calcium is a major mineral essential for healthy bones and teeth. There are several minerals known to be essential to the human body and which must be obtained from food. The major minerals (calcium, magnesium, phosphorus, sodium, chloride and potassium) are needed in the greatest quantities or are present in large amounts in the body. The three main functions of minerals are as constituents of the skeleton, as soluble

salts which help control the composition of the body fluids, and as essential adjuncts to the action of many enzymes and other proteins.

Calcium Requirements The UK Department of Health recommended Reference Nutrient Intake (RNI) for calcium is as follows. The RNI is a daily amount that is enough or more than enough for 97% of people. The RNI is similar to the Recommended Daily Amount used previously in the UK. Age/Sex Infants & children, depending on age Teenage girls Teenage boys Adult men & women Breast-feeding women

Calcium requirement (mg/day) 350-550 800 1000 700 extra 550

The 1989 US recommendations are generally slightly higher. In 1994 the US recommendations for children aged 1-10 was increased from 800mg to 1,200mg daily and for young adults aged 11-24 years it was increased from 1,200 to 1,500mg. During pregnancy and breast feeding women in the USA are now advised to have 1,400mg calcium daily and American men and women over the age of 50 years are advised to increased their calcium intake towards 1,500mg because the intestinal absorption of calcium declines with age.

Vegan Sources of Calcium Good plant sources of calcium include tofu (if prepared using calcium sulphate contains more than four times the calcium of whole cow's milk), green leafy vegetables, seeds and nuts. The calcium in green vegetables which are not high in oxalate e.g. kale, is absorbed as well or better than the calcium from cow's milk. Some soya milks e.g. Provamel, Plamil, Granovita are fortified with calcium. Drinking hard water can provide 200mg of calcium daily but soft water contains almost none. Other calcium rich foods include black molasses, edible seaweeds, watercress, parsley and dried figs

Examples of amounts of foods providing 100mg calcium Type of Food Black molasses Dried figs

20g 40g

Almonds Soya flour Parsley Kale Brazils Nuts Wholemeal bread

42g 44g 50g 67g 59g 185g

Protein & Calcium A high protein diet, especially derived from animal foods, causes calcium loss in the body. The higher sulphur-to-calcium ratio of meat increases calcium excretion, and a diet rich in meat can cause bone demineralisation. A report published in 1988 [1] comparing the amounts of calcium excreted in the urine of 15 subjects showed that the animalprotein diet caused greater loss of bone calcium in the urine (150mg/day) than the allvegetable protein diet (103mg/day). These findings suggest that diets providing vegetable rather than animal protein may actually protect against bone loss and hence osteoporosis. In one study adults on a low-protein diet were in calcium balance regardless of whether calcium intake was 500mg, 800mg or 1400mg a day. [2] Interestingly The American Dietetic Association, in its 1993 policy statement on vegetable diets, pointed out that the calcium intakes recommended in the USA were increased specifically to offset calcium losses caused by the typically high protein consumption in that country.

Calcium Absorption Only 20-30% of calcium in the average diet is absorbed. Calcium absorption can be reduced because it binds to fibre, phytate or oxalate in the intestine. Vegan diets contain more than average of these substances. Fibre is no longer thought to limit the availability of calcium from food. Phytate or phytic acid is found in grains, nuts and seeds and can bind with calcium making it less absorbable. However, the body does adapt to lower levels of available calcium and the American Dietetic Association and the UK's Ministry of Agriculture, Fisheries & Foods as well as the Department of Health believe that fibre, phytate and oxalate do not have a significant effect on calcium intake overall. Although the calcium intake of adult vegans tends to be lower than the recommended optimum, it is close to the Estimated Average Requirement. There have been no reports of calcium deficiency in adult vegans. The Estimated Average Requirement (UK) of a nutrient in the diet is an estimate of the average needs of a group of people. About half may need more, and half may need less.

Osteoporosis

Osteoporosis is the major cause of bone fractures in the elderly. One in four British women are affected by this disease. It is better prevented than treated and prevention includes an adequate intake of calcium throughout life, but especially in childhood and young adulthood; and minimising major risk factors e.g. smoking, heavy alcohol use and lack of physical exercise. Diets high in protein and in salt (sodium chloride) also increase calcium loss from the body and may have an effect on osteoporosis. Post-menopausal women are more prone to osteoporosis because they produce less oestrogen, which protects the skeleton in younger women. There has been much publicity about the role of dietary calcium in preventing osteoporosis but the fact remains that it is more common in Westernised countries where calcium intakes and consumption of dairy products are high compared to the rest of the world. Osteoporosis is comparatively rare in rural subsistence cultures, even though calcium intakes are much lower. Lifestyle factors, such as physical activity, lower protein intakes, little alcohol consumption and the rarity of smoking, may offer protection to people in these populations.

Cow's Milk & Health The advertising blurb surrounding cow's milk would make anyone think it is an absolutely essential and natural product for humans. Most people when thinking of increasing their calcium intake would immediately reach for a carton of milk or slab of cheese. However, there are several reasons for not using these products as a nutrient source. Whole cow's milk is suited to the nutritional needs of calves who double their weight in 47 days and grow to 300 pounds within a year. In fact, human beings are the only species to drink the milk of another species, and the only species to drink milk beyond infancy. In addition about 90% of the world's adult population (in Britain the figure is probably 25%) is deficient in the enzyme needed to digest milk properly. The enzyme lactase is present in infants for digesting their mother's milk, but levels decline after the age of five years. Adults who lack the enzyme suffer from bloating, cramping, wind and diarrhoea if they drink milk. The most significant connection between milk and ill-health is probably through its contribution to heart disease. Too much saturated fat in the diet can lead to atherosclerosis, where the arteries 'fur up' with cholesterol deposits and cannot deliver enough blood to the vital organs. The heart is particuarly susceptible. Milk and other dairy products account for about half of all saturated fats eaten in this country. Meat accounts for the rest. The UK has the highest level of heart disease in the world. Child-care expert Dr Benjamin Spock, once an advocate of drinking cow's milk, has joined several doctors questioning its nutritional value and warning of a possible link to juvenile onset diabetes and allergies. "Breast-feeding is the best milk feeding for babies," says Dr Spock. Dr Spock is backed up by Dr Frank Oski, director of pediatrics at John Hopkins University and Dr Neal Barnard, president of the 2000-member Physicians' Committee for Responsible Medicine. Dr Oski states that cow's milk is overrated as a

source of calcium, is often contaminated with traces of antibiotics, can cause allergies and digestive problems and has been linked to juvenile diabetes. [3]

Conclusions Vegans need to get at least 500 mg of calcium from calcium rich foods, such as tofu, fortified milks and greens, or supplements. Together with calcium from other less concentrated sources, this would give an overall calcium intake between 700 mg per day and 1000 mg per day. There is very little evidence that higher intakes than this would be beneficial. However, bone health is about much more than calcium. The fact that osteporosis risk is high in countries consuming relatively high amounts of calcium/dairy products illustrates this. Studies comparing individuals within developed countries also indicate that the benefit of calcium alone for reducing fracture risk is modest. Vitamins D and K may be more important while potassium (fruits, vegetables, roots and beans) reduces calcium losses and bone turnover and sodium (salt) increases these. Moderate, rather than low or high, protein intake is probably best. Physical activity plays a vital role. The best approach to prevention takes all these factors into account.

Essential Fatty Acids The main components of all fats are the fatty acids which might be saturated, monounsaturated or polyunsaturated. Fats containing a high proportion of saturated fatty acids are solid at room temperature. These are commonly known as saturated fats and are usually derived from animal sources e.g. lard, suet and butter. Most plant fats are high in either polyunsaturated or monounsaturated fats except palm and coconut fat which is highly saturated. Saturated and monounsaturated fats are not necessary in the diet as they can be made in the human body. Two polyunsaturated fatty acids (PUFAs) that cannot be made in the body are linoleic acid and alpha-linolenic acid. They must be provided by diet and are known as essential fatty acids. Within the body both can be converted to other PUFAs such as arachidonic acid, or eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). In the body PUFAs are important for maintaining the membranes of all cells; for making prostaglandins which regulate many body processes which include inflammation and

blood clotting. Another requirement for fat in the diet is to enable the fat-soluble vitamins A, D, E and K to be absorbed from food; and for regulating body cholesterol metabolism. Polyunsaturated Fatty Acids - Dietary Sources Food sources of the two main dietary polyunsaturated fatty acids (linoleic acid and alphalinolenic acid) are listed below. Linoleic Acid (Omega 6 family) • • • • •

Vegetables Fruits Nuts Grains Seeds

Good sources: Oils made from: • • • • • • •

Safflower Sunflower Corn Soya Evening primrose Pumpkin Wheatgerm.

Alpha-Linolenic Acid (Omega 3 family) (Please note - fish is not the only source of omega 3 acids. Flaxseed oil contains twice as much as is found in fish oil!). • • • • • • • •

Flaxseeds (linseeds) Mustard seeds Pumpkin seeds Soya bean Walnut oil Green leafy vegetables Grains Spirulina

Good sources Oils made from: • • •

Linseed (flaxseeds) Rapeseed (canola) Soya beans

EPA's and DHA's Alpha-linolenic Acid is converted in the body to EPA (eiocosapentaenoic acid) usually found in marine oil and DHA (docosahexaenoic acid) usually found in marine fish oil. Many factors affect the rate of conversion and one factor seems to be a high food intake of linoleic acid which is typical of vegan diets and may suppress the body's ability to convert alpha-linolenic acid to DHA. Vegans can achieve a better balance of PUFAs in their body tissues by using less sunflower, safflower and corn oils and more oils containing alphalinolenic acid such as rapeseed (canola) oil, or soya bean and walnut oils. This would encourage their tissues to make more DHA. Conclusions Numerous expert committees have recommended a reduced consumption of total fat by the general population. Only vegan diets generally comply with current guidelines that fat should not contribute more than 35% of the total energy intake of adults and older children. Saturated fats contribute to high levels of cholesterol in the blood, a risk factor for atherosclerosis and heart disease, while polyunsaturated fats (PUFAs) have the opposite effect. Vegan diets, containing no meat and dairy fats, are low in saturated fatty acids and high in beneficial PUFAs. Vegans consume considerably more of the essential PUFA linoleic acid than do omnivores, and approximately similar levels of the other essential PUFA, alpha-linolenic acid. Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), two non-essential PUFAs, do not occur in vegan diets. The human body can convert alpha-linolenic acid into EPA and DHA but, even so some of the body tissues of vegans contain less DHA and EPA than those of other dietary groups. The consequences of this difference, if any, are not known. Similarly, breast milks of vegans, vegetarians and omnivores contain differing proportions of various polyunsaturated fatty acids, and these differences are reflected in some body tissues of infants. It is not yet known what, if any, effect these variations may have on the growth and development of infants.