Читать книгу Why Men Don’t Iron: The New Reality of Gender Differences - Anne Moir - Страница 15

Back to the Arkansas study. If there were enough meat in the diet then men’s zinc deficiency would soon be solved, yet by adding more whole grains to the diet, which is what the nutritionists recommended, the overall availability of zinc might actually decrease owing to the action of the phytates in the unrefined cereals.

‘What’s going on?’ asks Bill. ‘Bran, oats, fibre-rich cereals … horse food.’

‘Health food,’ says Anne.

‘The phytates in them are zinc zappers. And they slurp up the iron the gut would otherwise take in.’

‘Unhealthy health food, then.’

Men need a ready, steady supply of zinc in their diet because a lack of it impairs the metabolism of androgens which are the essential male hormones.⁵⁶ And where is zinc most readily found? In red meat. Not in white flesh. A lean piece of beef has six times as much zinc as chicken breast and ten times more than in fish.⁵⁷ Wholemeal wheat may have almost as much zinc as the beef, but the phytates in the wholemeal block the zinc uptake. Phytates also bind with iron and calcium, two other essential micronutrients, and so prevent their absorption. Phytates are undesirable, but the protein in red meat acts as an anti-phytate agent.

This was well known by the mid-1980s,⁵⁸ but somehow red meat has become demonized, even though research has shown that young males brought up on a diet low in meat and heavy on wholemeal bread and unrefined cereals, as is common in some poor countries, experience a high proportion of growth defects. An example is the epidemic of rickets that occurred among the children of Dublin in the 1940s. The Irish Republic, though neutral in the war against Hitler, had been forced to impose rationing and the main bread in Dublin was whole-grain. The combination of the phytates in the bran – which removed the calcium from the diet – and too little Vitamin D, resulted in an epidemic of rickets and after three years of rationing nearly half the children in the city were suffering.⁵⁹

In Scotland the consumption of wholemeal bread has tripled since 1980. Women are mostly responsible for the increase and, unsurprisingly, a report on Scottish eating habits finds this trend ‘healthy’, while the males who continue to eat white bread are condemned as displaying a pattern of ‘unhealthy eating’. This judgement ignores the realities. Wholemeal bread does contain more vitamins and minerals than refined white bread, but much of that goodness is locked into the bran, which is indigestible. Unrefined flour also retains its outer aleurone layer which contains the undesirable phytates. Nutrients in white bread flour, though fewer because the germ and aleurone layers have been removed, are spared the effects of the phytates and so more of those nutrients are absorbed by the body. Additionally, because white bread is thought less wholesome, the nutrients are artificially added. Wholemeal flour, because it is deemed ‘natural’, is left unfortified.⁶⁰ The Scottish men also ate a seventh more red meat than their womenfolk, and this too was deemed to be ‘unhealthy’, though the researchers made no effort to distinguish between lean or fat meats, just as they appeared ignorant of the deleterious effects of phytates in wholemeal bread.⁶¹ Such is the current health-food wisdom: red meat unhealthy, white bread unhealthy – men are unhealthy.

‘The label on my wholemeal bread tells me that it’s full of goodness,’ Anne says.

‘What it doesn’t say is how it’s full of phytates blocking out that goodness,’ says Bill, ‘nor how the fibre in the bran speeds food through the gut and so acts as a mild laxative.’

‘Truly,’ said Anne, ‘wholegrain bread is one of the original fast foods. The good news is that it shouldn’t harm you if the rest of your diet is healthy.’

But what is thought to be healthy might very well not be. Current dietary recommendations do not take into account the poor bioavailability of minerals in the high-fibre diet so often associated with health food which, in its composition, is very like a Third World diet. They also overestimate the amounts of protein and energy that are available in such diets because too much fibre is assumed to be digestible.⁶² In rural Mexico anaemia is found in a third of men and pregnant women and in over half of non-pregnant women. ‘Low meat intake and poor dietary iron bioavailability were associated with anaemia in women.’⁶³

‘Health food …’ says Bill. ‘I guess by definition all else is unhealthy: get-sick-and-die-quick food.

‘Here’s the definition in my Collins Concise Dictionary,’ says Anne. “‘Health food n. vegetarian food organically grown and with no additives, eaten for its benefits to health”.’

‘Eaten with a cupboard full of artificial vitamin supplements from the health food store? Yet many a vegetarian lives long.’

‘Life outside the fast lane,’ said Anne. ‘Slow laps in the pool, aerobics and yoga: less risk and competition – more female than male. It’s not so much a lack of meat that makes for this long life, more a damped-down lifestyle. On the evidence to date, if the nice health-food people ate some nice red meat they’d live an even longer life. And be healthier too.’

Would nice-health food people be healthier if they overcame their repugnance for red meat? A diet containing varying amounts of lean ground beef was fed to young women by researchers in the Department of Home Economics at Illinois State University. For the first seven days all ate vegetarian. For the next three weeks they ate 3, 6, or 9 ounces of beef each day. Bodily iron increased the moment beef was introduced to the diet. Three ounces (85 grams) of beef a day was found to be the ideal amount, for there was no marked increase in the amount of zinc and iron absorbed when greater amounts of beef were eaten. This suggests that moderation is sensible. The researchers’ conclusion was that ‘zinc and iron utilization was enhanced after consumption of a diet including lean ground beef.’⁶⁴

‘A quarter-pound hamburger a day …’

‘… keeps the doctor away,’ says Anne.

Except that adding a wholemeal bun to the burger decreases the available iron. So does overcooking the meat. Cook meat to a grey death (an attempt, perhaps, to disguise its blood-origin and now required by law in the USA for hamburger, because of deep fear of bacterial contamination) converts the iron into the equivalent of plant-iron – which is ten times more difficult for the body to ingest. (See above, ‘Why men need iron’.) Medium done is better than well done.⁶⁵

Men are short of zinc, women of iron, and both are most easily found in red meat, yet that is precisely what is most often removed from the diet. Her need for red meat is much like his, if for different reasons, but her distaste for red meat is much greater than his. Some people, of course, eschew red meat for moral reasons, and fruitarians take this belief to its logical end by not only rejecting meat but even refusing to consume roots or leaves that cannot be eaten without killing the plant. Karen Nobel, a shiatsu practitioner from London, likes to eat up to 20 mangoes a day. ‘The thing about fruitarianism is that you are not murdering anything,’ she says. ‘It is delicious and it happens to be saving the Earth as well.’⁶⁶ Fruitarians tend to a dearth of iron, Vitamin B12 and essential fatty acids, and to flatulence and diabetes from the strain of producing insulin to break down the overdose of fruit sugars.

Karen Nobel turns orange during the mango season.