Since food, in the main, is no longer very nutritional, your only recourse is to supplement with vitamins and minerals. However, there are certain caveats to ensure that what you take is absorbed by your body.

* Don’t supplement indiscriminately. More isn’t always better. Certain vitamins (vitamin E and A) can be toxic in high levels. Furthermore, your body may be so biochemically efficient that it doesn’t need everything in certain nutrients. By the same token, your stomach acid may be so poor that you are not absorbing any of the pills you take.

* Don’t rely on the Recommended Daily Allowance. The RDAs are the minimum quantity of nutrient required to maintain metabolic balance or to prevent the development of a vitamin-deficiency disease. This single yardstick doesn’t take account of the needs of different cultural or ethnic groups, individual requirements or daily diets, or biochemical idiosyncrasies.

* Get tested. The Biolab Medical Unit in London (020 7636 5959) or Great Smokie Labs in the US (001 828 285 2223) can run a series of tests to determine which deficiencies you have from your diet which need to be corrected.

* How much you assimilate depends on many factors, including age, health, heredity and the state of your digestive system.

* Take extra minerals even if you already take a good multivitamin. Take it as read that you don’t get enough magnesium or zinc (no one does, anymore) and take extra supplements of each.

* Take minerals as citrates, fumarates, gluconates, amino acid chelates, aspartates or picolinates. Their absorption may rise to about 40 per cent.

* Avoid metallic or inorganic forms of minerals (such as oystershell, eggshell and the inorganic iron that pollutes all processed foods). If the pH (acid-to-base) balance is not right, calcium supplements are likely to be excreted (Earthletter, 1994; 4 [summer]: 7).

* Make sure you are getting enough fat-soluble vitamins and nutrients in your diet. These include vitamins E, A and D plus the essential fatty acids. To get the full complex of vitamin D (only one portion of which is made by sunlight on your skin), you need to consume seafoods, especially fatty fish such as herring and salmon, animal organs like liver, and dairy products, particularly cheese and butter, or to supplement.

* Avoid iron sulphates, which irritate the intestines.

* Don’t bother taking more than 500 mg per day of calcium. Anything over this isn’t well absorbed.

* Consider taking Celtic sea salts. To each quart of water, add up to half a teaspoon of Celtic sea salt in a jar and drink over the day. If no other mineral supplement is used, take a full half-teaspoon. Mineral analysis of Celtic sea salt in these quantities found ample levels of all the critically needed minerals in a readily bioavailable form. (For more information: www.watercure.com).