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Authors: Sarah Brewer

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Nutrition (30 page)

BOOK: Nutrition
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Calcium
Cutting out dairy products can result in a lack of calcium. Some types of fibre (phytates from wheat in unleavened bread – chapattis, for example) bind calcium in the bowel to form an insoluble, non-absorbable salt. In a high-fibre vegetarian diet, which speeds the passage of food through the bowels, the amount of calcium absorbed is also reduced. Vegans, with their traditional preference for wholemeal bread, could try calcium-enriched soy milk and include some white bread in their diet to counter the effects of their exceptionally high-fibre intake. Non-meat sources of calcium include: milk, cheese, yogurt, fromage frais, soy milk, green leafy vegetables, nuts, seeds, pulses, bread made from fortified flour, fortified cereals and eggs.
Vitamin D
Vitamin D is essential for the absorption of calcium from the small intestine but it is not found in many vegetarian foods, and that which is present in plants is in the form of vitamin D2, which is less well absorbed and used in the body than the animal form, vitamin D3. Some vitamin D3 can be synthesized in the body by the action of sunlight on a cholesterol-like molecule in the skin. Those living in high altitudes, who cover up their skin in sunlight or who stay indoors all day are not exposed to enough sunlight to meet their vitamin D needs. And once the UV index reduces to below 3, the skin reaction does not occur, so people living in northern climates are unable to synthesize their own vitamin D during most of the autumn and winter. Non-meat sources of vitamin D include mushrooms, eggs, fortified spreads, fortified cows’ milk and soy milk, fortified cereals and butter.
Zinc
Zinc deficiency is common in people who don’t eat meat. One of the earliest symptoms of zinc deficiency is loss of taste sensation. This forms the basis of a zinc-deficiency test that is widely available in pharmacies, and although it is not used by many orthodox nutritionists it is popular with nutritional therapists. A teaspoon of a solution of zinc sulphate (15 mg/5 ml concentration) is swirled in your mouth. If the solution seems tasteless, zinc deficiency is likely. If the solution tastes furry, of minerals or slightly sweet, zinc levels are borderline. If it tastes unpleasant, zinc levels are normal. Non-meat sources of zinc include brewer’s yeast, wholegrains, nuts, seeds, dark green vegetables, pulses, eggs and cheese.
What a typical healthy vegetarian diet includes
The following list outlines an ideal vegetarian diet that will provide maximum micronutrients. Aim to eat:
•    as wide a variety of foods as possible
•    home-made rather than pre-packed or processed meals, which usually have reduced nutritional value (unless fortified)
•    three to four servings of wholegrain products per day (e.g. bread, rice, pasta, buckwheat, polenta). These provide calories, protein, fibre, B vitamins, calcium and iron
•    at least 400 g vegetables and/or fruit per day in total (five portions) for vitamins, minerals, antioxidants and other beneficial phytochemicals
•    at least two pieces of fruit per day, one of which is a citrus fruit for vitamin C
•    dried fruits for fibre and iron
•    a large salad or portion of dark green leafy vegetables (e.g. spinach, watercress, broccoli, greens) per day for folate, calcium, iron and phytochemicals such as the carotenoid lutein
•    nuts, seeds, pulses and cereals provide protein, although none contains all the essential amino acids together. These foods need to be mixed and matched – e.g. the essential amino acid missing from haricot beans is found in bread. Hence, combining cereals with pulses or seeds and nuts provides a balanced amino acid intake. Aim for two to three servings of pulses per day for protein, energy, fibre, calcium, iron, zinc and vitamin E and 30 g nuts and seeds per day
•    two large portions of carrots or sweet potato (or yams) per week for antioxidant carotenoids such as betacarotene (which can be converted into vitamin A in the body)
•    textured vegetable protein (TVP) made from soybeans as an excellent source of protein, calcium, iron, zinc, thiamin, riboflavin and niacin
•    mycoprotein, derived from the fungus
Fusarium graminearum
as a good source of protein. Commercially available products can contain egg white, which is not suitable for vegans
•    one pint of semi-skimmed milk (or fortified soy milk) per day for protein, calcium and trace minerals
•    a serving of cheese per day for protein, calcium and minerals
•    a total of three or four eggs per week for protein, D and B group vitamins, iron, selenium plus omega-3 fatty acids – especially from free-range birds fed an omega-enriched diet
•    olive and rapeseed oils during cooking for important mono-unsaturated fats
•    butter (scraped on bread) for vitamins D and E
•    sources of vitamin B12, e.g. fortified soy milk, fortified breakfast cereals, fortified yeast extracts, Protoveg or supplements.
For many people, over-nutrition is a big problem – and ironically this often goes hand in hand with a deficiency of key vitamins and minerals. Put simply, excess energy intake coupled with insufficient physical exercise leads to weight gain and, worldwide, obesity has more than doubled since 1980. According to the World Health Organization (WHO) that monitors global data, in 2008 1.5 billion adults aged 20 and over were overweight. Of these, 200 million men and nearly 300 million women were obese. This means that, overall, more than one in ten of the world’s adult population is obese. In 2010, nearly 43 million children aged under five years were also overweight. These are harrowing figures, given the problems that obesity can lead to, and given that obesity is a totally preventable condition.
Our genetic time bomb
The genes that enabled cavemen to survive during conditions of alternating feast and famine are now working against us. Five hundred generations ago, when a large animal was killed, our primitive ancestors ate as much as they could in one go, as meat was less easy to preserve for future use as it is today. When gorging in this way, over a short period of time, the rapid conversion of dietary protein and fat into body-fat stores allowed for survival over the following days, weeks, or even months until the next significant source of food became available. Those whose genes promoted fat storage in this way survived better than those less genetically adapted to this way of life. Although food scarcity is still a problem in many parts of the world, affluent countries are battling with the opposite problem – an excess of calories, which our genes still store away for a future famine that never arrives. As a result, obesity rates are high – and increasing – in many countries, as shown in
Table 20
. In less affluent countries the rates are much lower. In India, for instance, only 9 per cent of adults are overweight and 2 per cent are obese.
Dietary excess is just as harmful to health as dietary lack, if not more so, as it increases the risk of life-shortening diseases such as coronary heart disease, stroke, Type 2 diabetes and some cancers. Conversely, as mentioned in the introduction to this book, a low-calorie intake is associated with longevity as long as there is no associated deficiency of vitamins and minerals.
Prevalence of excess fat in adults
Country
% overweight
% obese
Albania
49%
29%
Iceland
41%
18%
Germany
38%
21%
Australia
37%
25%
England
37%
25%
US
35%
34%
New Zealand
35%
25%
France
33%
17%
Bahrain
32%
27%
HEALTH RISKS OF OBESITY
Carrying excess weight is associated with high blood pressure, raised cholesterol levels, poor glucose tolerance and Type 2 diabetes, all of which, in turn, increase your risk of experiencing a heart attack or stroke.
•    obesity doubles the risk of dying prematurely from coronary heart disease and stroke
•    obesity increases the risk of Type 2 diabetes almost fortyfold, especially when excess fat is deposited around the abdomen and where weight is gained after the second decade of life – whatever the starting weight
•    obesity doubles the risk of developing asthma
•    someone who is obese will die, on average, seven years earlier than someone in the healthy weight range for their height
•    severe obesity (BMI > 40 kg/M
2
) is linked with up to a twelvefold increase in mortality among young adults compared to those who are in the healthy weight range for their height.
Your body-fat stores can be estimated using a calculation in which you divide your weight (in kilograms) by your height in metres and divide by your height again, as follows:
BMI = weight (kg) ÷ height (m) ÷ height (m)
This gives a number, called your Body Mass Index (BMI), which the World Health Organization interprets as follows:
WEIGHT BAND
BMI (kg/m
2
)
Underweight
< 18.5
Normal range
18.5 to 24.9
Overweight (pre-obese)
25 to 29.9
Obese
> 30
You can find the ideal weight range for your height in
Table 21
, which is based on a BMI of 18.5 kg/M
2
to 24.9 kg/M
2
(calculations rounded up or down as appropriate).
Height
Optimum healthy weight range
Metres
Feet
Kg
Stones
1.47
4' 10"
40.0–53.8
6 st 4 lb–8 st 6 lb
1.50
4' 11
41.6–56.0
6 st 8 lb–8 st 11 lb
1.52
5'
42.7–57.5
6 st 10–9 st
1.55
5' 1"
44.4–59.8
7 st–9 st 5 lb
1.57
5' 2"
45.6–61.4
7 st 2 lb–9 st 9 lb
1.60
5' 3"
47.4–63.7
7 st 6 lb–10 st
1.63
5' 4"
49.2–66.2
7 st 10 lb–10 st 5 lb
1.65
5' 5"
50.4–66.6
7 st 13 lb–10 st 7 lb
1.68
5' 6"
52.2–70.3
8 st 3 lb–11 st
1.70
5' 7"
53.5–72.0
8 st 6 lb–11 st 4 lb
1.73
5' 8"
55.4–74.5
8 st 10 lb–11 st 10 lb
1.75
5' 9"
56.7–76.3
8 st 13 lb–12 st
1.78
5' 10"
58.6–78.9
9 st 3 lb–12 st 5 lb
1.80
5' 11"
60.0–80.7
9 st 6 lb–12 st 9 lb
1.83
6'
62.0–83.4
9 st 10 lb–13 st 1 lb
1.85
6' 1"
63.3–85.2
9 st 13 lb–13 st 5 lb
1.88
6' 2"
65.4–88.0
10 st 4 lb–13 st 11 lb
1.90
6' 3"
66.8–89.9
10 st 7 lb–14 st 1 lb
1.93
6' 4"
68.9–92.8
10 st 12 lb–14 st 8 lb
BOOK: Nutrition
11.69Mb size Format: txt, pdf, ePub
ads

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