To clarify requirements for essential nutrients, the National Health and Medical Research Council, with the Australian and New Zealand government health departments, has come up with a set of nutrient reference values.
Each nutrient is assigned the following values:
- Estimated average requirement (EAR) according to age and gender and, if female, whether pregnant or breastfeeding
- Recommended dietary intake (RDI) deals with variation in absorption or metabolism of each nutrient
- Adequate intake (AI)
- Upper level of intake (ULI) regular intake above this level could have adverse effects.
The new recommendations cover a wider range of vitamins and minerals than in the past, including omega-3 fats, dietary fibre, water, vitamin K and fluoride.
Increased intakes are recommended for some nutrients, including folate and other B vitamins (thiamin, niacin, riboflavin, vitamin B6 and B12), plus calcium and magnesium. More folate is recommended because nutrition experts now recognise the difference between the two forms naturally occurring food folate and the supplement folic acid. The latter is twice as well absorbed as food folate.
Recommended intakes for calcium are bumped up because it is now understood that some 60mg a day is lost through sweating.
Recommended intake of salt (sodium) has decreased substantially, more so for those at greater risk of developing high blood pressure.
Nutrients which may be borderline are folate, calcium and iron in women, plus selenium and iodine.
Vitamin and mineral supplements are not required to get all the nutrients you need, as long as you eat plenty and various vegetables and fruit (including some seeds and nuts), wholegrain cereals, reduced-fat diary foods and lean meats, fish (especially if rich in omega-3 fats) or poultry, as well as small amounts of poly or monounsaturated fats and oils.
Numerous vitamins and minerals can interact with others in good or bad ways. Very high intakes of iron, for instance, may interfere with the absorption of zinc, because both use the same method. Vitamin C, for instance, can help with absorption of nutrients like zinc if consumed at the same time. Some medications can affect the body's ability to absorb and use nutrients.
A good balanced diet
If you are tired all the time, don’t sleep well, have skin problems or feel depressed and listless, look to your eating habits. Eat a balanced diet containing fresh foods from the following five food groups every day.
- Bread and cereals, for energy from carbohydrates, fibre, some protein, vitamins and minerals.
- Vegetables and fruit, for vitamins, minerals and fibre.
- Meat and meat alternatives, for protein, vitamins and minerals, especially iron.
- Milk and milk products, for calcium, protein and vitamins.
- Fats and oils, for energy, vitamin A and to help assimilate vitamins and minerals from food.
Grain products: bread, cereals, rice, pasta and oatmeal.
Vegetables and fruit.
Protein-rich foods: lean meat, poultry, fish, eggs and legumes and dairy products.
Fats, sugar, salt, tea, coffee, soft drinks, alcohol.
All material is © Media 21 Publishing, and originally appeared in the December 2006 issue of Good Medicine magazine.