They are:

Omega-3 oils are now known to act on the blood platelets, making blood clots less likely. Omega-3 oils are found mainly in oily fish - sardines, pilchards, salmon, herring, kippers, mackerel, fresh tuna, trout and anchovies. Fish oil supplements do the same job and if you do not eat fish at all they are worth adding to your diet.

A healthy heart and arteries tops this list for obvious reasons. All kinds of nutrients are needed to keep the cardiovascular system in good order (see below), but omega-3 oils deserve a special mention here.

Calcium is essential to keep bones healthy but most of don't consume enough of it. On the other hand, there is not evidence that a high intake helps protect bones.

Calcium is found in milk (semi-skimmed has more than whole milk) and other dairy products, the soft bones in canned fish, bread, pulses, leafy green vegetables, dried fruit, nuts and seeds. A pint of milk a day will supply all the calcium we need - 700mg.

We need vitamin D to enable our bodies to use the calcium in food.

Vitamin D is mainly sourced from the sun acting on our skin, and not from our diet at all. It is vital for all of us to get (careful) exposure to the sun in the summer months. Those who cannot get out, or keep their skin covered, should consider a vitamin D supplement, especially in the winter (though note that vitamin D is poisonous if taken to excess).

Some margarines are fortified with vitamin D.

Zinc is involved in the metabolism of proteins, carbohydrates and fats. A lack of zinc will affect tissues that need constant renewal and repair such as the skin, the lining of the gut and the immune system.

There is evidence that older people with poor wound healing, and particularly leg ulcers, are not getting sufficient zinc. Lack of zinc is also a factor in dementia. This vital mineral is found in meat and meat products, seafood, milk and dairy products, wholemeal bread, lentils, eggs, nuts, sweetcorn and rice.