Sunday, June 18, 2006

The new food challenge

Here is an article that appeared in The Melbourne Age on the 15th of June.

The latest official advice on nutrition sets the dietary bar higher than ever.

In 1954, the year Germany won the World Cup and Marilyn Monroe married Joe DiMaggio, health authorities published Australia's first Recommended Dietry Intakes (RDI)- the amounts of nutrients considered essential to keep Australians healthy and prevent deficiencies that caused problems like scurvy and rickets.

Half a century later, new dietary recommendations, including updated RDIs released by the National Health and Medical Research Council in May, show how far nutrition science has come in recognising the power of food to help fight disease.

What distinguishes the 2006 RDIs from those produced in 1954, and the years in between, is that they come with a companion set of guidelines that aims to help prevent modern plagues such as heart disease, cancer, macular degeneration and Alzheimer's disease.

Eating nutrients in the amounts suggested in the new RDIs will help keep us in acceptable health, but these extra guidelines, called Suggested Dietary Targets, encourage us to eat even greater amounts of selected nutrients, because evidence shows that eating them at higher than recommended daily intakes may help prevent chronic disease.

This drives home the message that we do have some control over our health and that what we choose to toss into the shopping trolley or the saucepan really makes a difference - a point recently underscored by the Dutch National Institute for Public Health and the Environment, which ranked low consumption of vegetables, fruit and fish as just as bad as smoking for human health.

It also raises the bar both for us and Australia's food industry. If you're already struggling to reach the current target of five servings of vegetables a day and two of fruit, for instance, you'd better lift your game. To reach the new recommendations for some vitamins, you may need to eat six to seven serves of vegetables and three or four serves of fruit, estimates Professor Sandra Capra, head of the School of Health Sciences at Newcastle University and a member of the working party that developed the new guidelines.

More challenging still could be shrinking our sodium levels to sidestep the high blood pressure affecting one in six of us. The upper limit of the old RDI for sodium was 2.3 grams; the new SDT is 1.6 grams daily - less than a teaspoon of salt from all food sources.

Capra says this is probably achievable by not adding salt to food, eating more fresh produce, and giving most processed food and takeaways a wide berth, but many people will find it a struggle.

Still, if that seems unrealistic, chew on this: is it any more unrealistic than expecting bodies that evolved to eat plants and wild game to thrive on instant noodles?

Part of the solution will be getting the food industry to lower salt levels in processed food - which, along with takeaway food, is the source of 75 per cent of Australia's sodium intake - suggests Dr Caryl Nowson, who is professor of nutrition and ageing at Deakin University and one of a panel of experts who reviewed research for the NHMRC working party.

It's a strategy already in force in Britain, where major food chains such as Sainsbury's, and Marks and Spencer, have lowered the salt content of their bread.

So what do the new Recommended Daily Intakes and Suggested Dietary Targets mean when it comes to breakfast, lunch and dinner? At this stage, these recommendations are more a guide for health professionals and a basis for changing food labels - as yet, there's no healthy eating plan available to show us how to apply them to what we eat and it may be some time before the Federal Government produces one.

Meanwhile, this snapshot of some of the recommendations will give you an idea of the challenge.

The RDIs for calcium have risen for children and adults of all ages, but they're especially high for teenagers, women past menopause and men over 70, who now need 1300 milligrams a day - about four serves of dairy foods. The reason for the rise is evidence that some calcium is lost in sweat. How to get more Low-fat dairy products aren't the only calcium food (canned fish with edible bones and almonds are among others, as are green, leafy vegetables), yet they're considered the best because lactose helps you absorb calcium.

Three serves of dairy products could deliver the old target of 1000 milligrams daily for teenage girls and women over 50. However, Nowson isn't sure that adding a fourth serve to meet the new requirements is ideal - except perhaps for active adolescents - as it hardly fits with the goal of eating a wide variety of foods. Her advice is to choose dairy products fortified with extra calcium, while older people may need a supplement.

This B vitamin (called folacin in its synthetic form) reduces levels of an amino acid called homocysteine, which is thought to increase the risk of heart disease, and also seems to help prevent cancer in a number of ways - including reducing damage to DNA. Drinking alcohol increases the body's need for this vitamin. The new RDI for folate is now double the amount of the last (1991) RDIs - as much as 400 micrograms for adults and teenagers, for example.How to get more Vegetables, including dark green, leafy vegetables are good folate foods, but given our woeful vegetable consumption - studies suggest only 12 per cent of our vegie intake comes from leafy greens, while 42 per cent comes from potatoes - the chances are many of us aren't close to getting even the old RDI for folate.

Meeting the new RDI means not just getting serious about more fruit and vegetables, but choosing them carefully. Compared to a nutritional lightweight - iceberg lettuce, for instance - vegetables such as spinach, broccoli and beetroot have more folate. Other good folate foods include liver, oranges, avocado, lentils and chickpeas.

"While we can keep telling people to eat more and more vegetables, the reality is many people won't reach the targets," Nowson says. "Eating more foods such as fruit juice and wholegrain breakfast cereals that are fortified with folic acid may be more realistic."

Food is the best way to get your daily folate because of all the other nutrients that come with it, but folate in supplement form is well absorbed, Capra adds.

The Suggested Dietary Targets for some vitamins, including vitamins A and C, are much higher than the Recommended Daily Intakes. The new RDI for vitamin C for men is 45 milligrams daily, for instance - roughly the amount in a medium mandarin - though the Suggested Dietary Target is almost four times this amount.

The reason is that these vitamins act as antioxidants that may help prevent some chronic diseases. Carotenoids, which are found in red, yellow and orange vegetables (and which your body needs to make vitamin A) may reduce the risk of cataracts and macular degeneration, for example. How to get more Recommended amounts for both vitamins are higher, but this doesn't mean you need to eat more food, just better food. Out go nutrient-poor drinks and foods - in come brightly coloured vegetables and fruit, and legumes.

In the past we had no guidelines for vitamin D intake; it was assumed Australians got enough from sunlight. Now there's evidence that some people - including elderly people in nursing homes, people with darker skins and women who are veiled for cultural reasons - don't get enough and are at risk of osteoporosis. Without sufficient vitamin D, we can't absorb enough calcium to keep bones in good shape. How to get more Unless you're big on eel or mackerel, it's difficult to get enough vitamin D from food, Nowson explains. Without enough sunlight, you'll need a supplement, or foods fortified with vitamin D. "Ideally, of course, we'd be redesigning nursing homes and increasing staff levels, so it would be easier to get elderly people out into the sun each day," she adds.

The NHMRC recommends 10 micrograms daily for people over 50 and 15 micrograms for over-70s. But too much can be toxic - the NHMRC sets an upper limit of 80 micrograms for adults.

For enough sunlight for your body to make vitamin D, you need to expose hands, face and arms (or an equivalent area of skin) to sunlight for about five to 15 minutes, four to six times a week. People who are elderly or who have darker skins need more sunlight exposure; about 15 minutes, five to six times a week.

The Suggested Dietary Target for omega-3 fats - found mainly in oily fish - is a high 610 milligrams for men and 430 milligrams for women, but that's the level at which the research says there's a benefit for reducing heart disease and stroke. There's also emerging evidence that these healthy fats may protect against rheumatoid arthritis, asthma, depression and dementia. How to get more. About 10 per cent of Australians meet the new Suggested Dietary Target of omega-3 fats, but most people average less than 100 milligrams daily, says Andrew Sinclair, professor of human nutrition at Deakin University. He's the first to admit that it isn't easy. Many rich sources of omega-3 fats - fresh salmon, rainbow trout and snapper, for example - are expensive, while others including, canned mackerel or sardines, aren't hugely popular.

As for canned tuna, you'd need to eat two to three 100 gram cans daily to reach the SDT. However, a weekly splurge of fresh salmon (about 150 grams for a woman and 200 grams for a man) would provide around seven days' supply of omega-3 fats in one hit (but doesn't solve the problem of depleting fish stocks if there's a rush on oily fish).

The best advice, says Sinclair, is to eat oily fish regularly (trevally is a cheaper option) if you can, include walnuts, and flaxseed oil (which help your body make omega-3 fat), and foods such as eggs that are enriched with omega-3 fats.

Lean red meat has some omega-3s - 30 to 60 milligrams per 100 grams. Good quality fish-oil capsules arealso a safe option, he adds.

The new recommendations, including the RDIs and SDTs, as well as the maximum safe intakes of nutrients, are in the report Nutrient Reference Values for Australia and New Zealand, and can be seen at:

The link above points to a PDF file. If you don't already have Adobe PDF reader, you can download it (free) from the logo on the left.

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