Is it true that drinking green tea can make you live longer?

Research suggests that green tea has antioxidant, antithrombotic, antiviral, antibacterial and anti-cancer properties, and may help to lower bad cholesterol. Researchers in Hong Kong also found recently that people who drank three cups a day had longer telomeres — the repetitive DNA sequences at the end of chromosomes that normally shorten with age — than others. They suggest that chemicals called flavanols in green tea help to keep cells younger. Green tea is also known to help to fight gum disease and possibly mouth cancer.

Would changing my diet help my wife to conceive?

One small study has suggested that sub-fertile men tend to have less zinc in their seminal plasma than fertile men, and that zinc levels seemed to be linked to sperm count and sperm development.

Foods that are good for zinc include lean red meat, wheatgerm, crab, sardines and shellfish (especially oysters).

Environmental pollutants, such as dioxins and organochlorines, may also have an adverse effect on sperm health. The foods most likely to contain these are those rich in fats, such as fatty meat products and full-fat diary foods.

My boyfriend says smoothies are all the fruit he needs

The recommendation is to try to eat at least five portions of fruit and vegetables a day. Until recently, a glass of fruit juice was considered to count as one portion.

Now, the Department of Health has decided that if a (250ml) smoothie contains the crushed pulp as well as the juice of two different pieces of fruit, it can count as two of your five a day.

Even so, whole fruit is more filling because it needs to be chewed and your stomach has to do all the digesting.

Furthermore, however fresh-looking a smoothie appears, its contents have had to be preserved in some way to give the product a shelf life of about 20 days — so you should find more heat-sensitive and light-sensitive nutrients, including vitamin C, in real fruit.

Can dried apricots trigger asthma attacks?

Sulphur dioxide is a preservative that can take the form of salts known as sulphites. These are used in everything from fruit drinks, wine, cider and beer to pickled onions, packets of mashed potato and dried fruit such as apricots. Their main role is to prevent browning.

Between 3 and 10 per cent of people with asthma are so sensitive to sulphites that they may trigger an attack. Brown apricots — minus these preservatives — give us iron, calcium and fibre with no risk for those with asthma.

For a further Q&A with Amanda and a fitness Q&A session with Matt Roberts, visit timesonline.co.uk/healthclub. If you have a nutrition question, e-mail amanda.ursell@thetimes.co.uk