With its emphasis on fresh fruits and veggies, fish and olive oil, the Mediterranean diet is regarded as a healthy feeding regime, and one that seems to be particularly effective in warding off heart disease. While I am enthusiastic about this way of eating, I am not so keen on certain foods such as pizza and pasta that are associated with this diet on account of their Italian origins. The consumption of the refined flour on which these foods is based can induce biochemical changes in the body that have been linked with conditions such as diabetes (see Nutrition News, below), obesity and heart disease.
I was therefore interested to read a recent report in the British Medical Journal which alerted me to a study in which pizza-eating was found to protect against heart attacks. Could it be that pizza is not such a roundly unhealthy food after all?
In an effort to get to the bottom of what has been coined the 'Italian enigma', I turned my attention to the research on which the BMJ report was based. In this study, published in this month's edition of the European Journal of Clinical Nutrition, the association between pizza-eating and heart-attack risk was assessed in a group of 1,000 Italians, half of whom had recently suffered a heart attack. Compared to individuals who did not eat pizza, those eating it at least once a week had a reduced heart-attack risk of 40 per cent. For those eating pizza at least twice a week, the risk appeared to be slashed by more than half.
It is important to bear in mind that a study of this nature does not necessarily prove that pizza is protective for heart disease, as those eating pizza may have a reduced risk of heart disease due to favourable differences in what are known as confounding factors (such as smoking habits, alcohol consumption and body weight).
Yet even when such things were accounted for, the apparent protective effect remained. Analysis of the main ingredients of pizza (such as tomato and olive oil) and their relationship with heart disease did not yield a satisfying solution either. But further analysis did reveal that the pizza-eaters had a higher intake of a range of heart-healthy nutrients such as omega-3 fats, folate and potassium. It may be not pizza per se, but the tendency for pizza lovers to eat a relatively nutritious diet that is the most likely explanation for the Italian enigma.
My advice to those wishing to eat pizza would be to opt for thin-crust varieties (these are less likely to cause the sort of carb-loading that can be so disruptive to the body's biochemistry), along with a salad for nutritional balance. While recent reports suggest that pizza is a healthy food, a close look at the dietary data has left me feeling flat.
Dear John
Please settle a little question for me. I've read that chocolate contains chemicals that simulate the feeling of being in love. Is this true?
Kathryn P
Chocolate contains a range of psychoactive chemicals, including phenylethylamine. This substance occurs naturally in the brain, and is believed to be secreted in higher amounts when we are in love. It is also found in the cocoa component in chocolate, so consuming chocolate rich in cocoa (dark chocolate) gives you the best chance of getting any mood-enhancing effect. There is some doubt about whether the amounts of phenylethylamine found in even dark chocolate are enough to have any significant effect. But there are other good reasons to opt for dark over milk chocolate: cocoa is also rich in a range of nutrients including magnesium, potassium, iron and heart-healthy substances called polyphenols. Also, as I pointed out in a recent column, the darker the chocolate, the less sugar it contains. For a multitude of reasons, I advise those who like to eat chocolate to choose varieties which contain 70 per cent or more cocoa solids.
If you have any issues you would like Dr Briffa to address in his column, please email him on john.briffa@observer.co.uk. Please note that Dr Briffa cannot enter into any correspondence. You can also visit drbriffa.com.
Before following any recommendations in this column, you should consult your own medical adviser about any medical problems or special health conditions
Nutrition news
The speed and extent of sugar release from a carbohydrate-rich food can be quantified in a measurement known as the glycaemic index (GI). Foods with high GI tend to bring on a substantial release of blood sugar, which in turn will stimulate the body to secrete relatively large amounts of the hormone insulin. In the long term, elevated levels of insulin may cause the body to become relatively unresponsive to the effects of insulin, which has the potential to lead to type 2 diabetes in time.
In a study published this month in the journal Diabetes Care, Australian researchers assessed the relationship between the consumption of white bread (a high GI food) and the development of diabetes in a group of almost 32,000 non-diabetic individuals. Over the four years of the study, those consuming the most white bread were found to be at 37 per cent increased risk of developing diabetes compared to those eating the least white bread. This study supports the notion that consuming quantities of relatively high GI foods (such as white bread, pasta and potato) may increase risk of diabetes. Swapping these for lower GI foods, such as whole rye bread and wholewheat pasta, may afford relative protection from diabetes.
