The truth behind the headlines

Red meat causes cancer, coffee raises cholesterol and fish oils don't protect against heart disease. Hardly a week goes by without some food scare appearing in the media. That's why we've asked Yahoo's registered nutritionist, Rachael Anne Hill to sort fact from fiction and reveal the truth behind some of the recent headlines……

Headline: Coffee raises cholesterol and causes heart disease
Coffee has been blamed for a whole host of health problems over recent years including heart disease, diabetes and even cancer. However, experts now believe that this link may be more to do with the fact that coffee drinkers tend to smoke more and consume more alcohol than the coffee itself.

In fact, there is a growing body of evidence to suggest that far from causing these diseases the antioxidants present in coffee may actually help to prevent them. However, this doesn't mean that coffee should be used as a replacement for fruit and vegetables or even that non-coffee drinkers should think about taking up the habit but it does enable those that consume a moderate amount (4 to 5 cups a day) can continue to do so without worrying too much about the effects it may have on their health.

[See also: The '5 a day' message - essential for health or just hype?]

Coffee can be a good way of including milk and therefore calcium in the diet and as long as you don't load up the calories by adding lots of sugar and cream a moderate intake of 4 to 5 cups a day is not likely to do any harm. However, if you are pregnant, limit your intake of caffeine to no more than 300mg per day from all sources including colas, tea and coffee. As a guide, coffee has up to 100mg of caffeine per cup, tea has slightly less at a maximum of about 70mg per cup and colas have up to 45mg per 12oz can.

Headline: Fish oils don't protect against heart disease
A paper published in the British Medical Journal sparked media frenzy when it seemed to imply that there maybe little or no strong evidence of omega 3 intake on cardiovascular disease. However, the paper didn't actually say that fish oils are not beneficial to health. Instead, it simply highlighted the fact that further research is needed to determine the doses required for potential cardiovascular benefits.

It is still essential to get plenty of omega-3 oils in our diets. In addition to helping your heart by reducing cholesterol and lowering blood pressure they play an important role in keeping brain tissues healthy. This can help to prevent Alzheimer's in adults as well as having possible benefits for conditions such as dyslexia, ADHD and dyspraxia.

They can also help to relieve symptoms of inflammatory bowel disease and arthritis. Wherever possible, try to obtain your omega three fatty acids from real foods such as oily fish, nuts and seeds rather than relying solely on supplements. Not only are the fats utilised more easily by the body when taken in their natural form but you'll also benefit from a whole load of other nutrients such as protein, iron for energy, iodine to boost the metabolism and calcium for strong, healthier bones.

Headline: Aspartame causes brain tumours

There has been a lot of interest in the media regarding the safety of aspartame (also known as NutraSweet or E951). Symptoms of dizziness, headaches, changes in mood and impaired vision have been attributed to its use but are unsubstantiated by published research. Concern about the carcinogenic potential of aspartame was raised by a report linking its consumption with brain tumours in the US. The research in question found the introduction of aspartame into the US food market to have occurred several years prior to a rise in the incidence of brain tumours and therefore suggested a link between the two. However, no direct relationship was found.

Experts have since questioned the reliability of the paper as, not only were the experiments carried out on rats, not humans but the rats were a species prone to naturally develop high incidences of cancers and brain tumours. Critics also point out that the number of people consuming aspartame since 1981 has rocketed whilst the incidence of brain tumours has remained fairly constant therefore weakening the likelihood of there being link between the two.

The acceptable daily intake for aspartame is 40 milligrams per kilogram of body weight. This is the level considered not to present any appreciable risk to human health, even if consumed everyday for a lifetime. Studies show that even those likely to consume a wide range of sweetened foods, such as diabetics and dieters still have intakes well below this amount. However, if you are concerned about consuming too much aspartame limit your intake of foods that are likely to contain it such as diet drinks, desserts and yogurts.

Headline: Soya can protect women against breast cancer
Some studies have suggested soya may have a protective effect against breast cancer, others haven't. The problem is that even if soya can help, most people in this country simply don't eat enough of it as in order to have any significant effect women would need to eat approximately 25g a day. When compared to the 1g per day that most women currently eat this is quite a tall order to achieve.

The best nutritional strategy to limit your risk of breast cancer is to eat plenty of fruit and vegetables, maintain a healthy body weight, include healthy unsaturated fats in the diet from oils, nuts, seeds and fish and reduce your intake of processed foods, saturated fats and alcohol.

Headline: Vitamin C does not prevent colds
The idea that high levels of Vitamin C can protect against the common cold has been around for a long time but there is very little evidence to support this claim. There are some small studies that suggest that a diet rich in Vitamin C may be effective in helping to reduce the severity or duration of a cold but this too is highly questionable.

Despite the lack of evidence to support the efficacy of Vitamin C against the common cold it is still vital that a good intake is maintained by eating plenty of fresh fruit and vegetables as it is a great anti-oxidant that has numerous other health promoting properties.

Headline: Products containing plant sterols can lower cholesterol

There are over 60 types of plant sterol. They are naturally present in small quantities in many fruits, vegetables, nuts, seeds, cereals, beans, and other plant foods containing fats and oils. They are also added to a number of premium priced margarines, milk products and yogurts. The most common form added to commercially prepared foods is beta-sitosterol. They function as cholesterol-lowering agents in blood by blocking the absorption of cholesterol from food during digestion and also by blocking the re-absorption of cholesterol manufactured in the liver.

People with normal levels of blood cholesterol have little to gain from eating these products. They may, however, be beneficial to those with high cholesterol but only if used in conjunction with plenty of regular exercise and eaten in significant amounts (2 — 3 servings a day) as part of a healthy, high fibre, low fat diet.

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