05 January 2006

Sensational diet and food stories

Have you ever received e-mail warnings that read something like “Food X will make you blind, impotent, or give you cancer”, or “Additive Y is a carcinogen, and may cause ADHD”?

Have you ever received anonymous e-mail warnings that read something like “food X will make you blind, impotent, or give you cancer”, or “additive Y is a carcinogen, and may cause ADHD, or multiple sclerosis”?

If you surf the Internet, you will also have come across entire websites dedicated to warnings and horrendous scare stories about foods, fluoridisation of drinking water, additives, and a host of related subjects.

Two of the questions recently posted to DietDoc were related to the following foods or food products:

  • Aspartame: certain sources claim that this sweeteneer may cause severe illness.
  • Fruit: some say fruit can be "harmful" in terms of blood cholesterol levels.

Here, DietDoc takes a closer look at these two issues:

Aspartame is an artificial sweetener that is manufactured from an amino acid called phenylalanine. The accusations levelled against this sweetener are bizarre and colourful and not based on scientific evidence.

Keep in mind that most people who can afford to eat meat, fish, eggs, milk and dairy products will ingest more phenylalanine on a daily basis than from aspartame.

A large number of studies have found that aspartame does not cause attention deficit hyperactivity disorder (ADHD) or multiple sclerosis, or any one of the many other diseases and conditions that the scare e-mails and websites assure you will occur if you use aspartame.

Before any new food product, such as aspartame, is allowed to be sold to the general public, the manufacturers have to subject it to extensive testing to determine whether it is safe for human consumption. Usually such tests are first conducted with experimental animals to determine if the food or sweetener causes any disease condition, such as cancer, genetic effects, nerve degeneration, weight gain or any metabolic abnormalities.

If the product passes this first hurdle, it is fed to the experimental animals in massive doses, which far exceed any human intake. If the product passes this second hurdle, it is usually tested on human volunteers who are monitored closely. If no changes in metabolism, genetic potential and/or behaviour are noted, the product is classified as “Generally Safe for Human Consumption (GRAS)” and is allowed to be sold.

Both national and international organisations are responsible for verifying if such a product is safe, e.g. the World Health Organisation (WHO) and our own Department of Health.

In view of the exhaustive nature of the controls exercised over such new food products, the public can rest assured that sweeteners like aspartame will not cause harm and that if an individual wants to use aspartame they can do so.

Who should not use aspartame?
A small number of individuals who suffer from an inherited, genetic disease called phenylketonuria, cannot use aspartame because it contains the amino acid phenylalanine. These individuals should avoid all sources of phenylalanine, including the foods listed above as sources of this amino acid.

Foods and beverages sweetened with aspartame all carry a warning directed at phenylketonuria sufferers to warn them that the products contain phenylalanine and that they should be avoided by phenylketonurics.

The rest of the population who do not have a deficiency of the enzyme required to metabolise this amino acid, can use aspartame without problems.

Are certain fruits harmful to cholesterol levels?
There is also no scientific basis to this scare story. Fruits and vegetables are rich sources of vitamins, minerals, dietary fibre and bioflavonoids, which help to protect us against heart disease. Fruits and vegetables can also help to lower raised blood cholesterol levels, especially those with a high dietary fibre content.

When are certain fruits harmful?
However, some people who suffer from heart disease have raised triglyceride levels – another type of fat that can be increased in individuals who have heart problems. Triglyceride levels in the blood are influenced by the amount of carbohydrate and food sugars the person eats.

Patients with so-called hypertriglyceridaemia (raised triglyceride levels), are cautioned not to eat excessive amounts of sugar, refined carbohydrates with a high glycaemic index (GI) and certain fruits, namely very sweet fruits, like grapes, or tropical fruits, which have a higher GI and sugar content, than deciduous fruits such as apples, pears and plums.

If you suffer from hypertriglyceridaemia, you need to eat a diet based on foods with a low GI and reduce your intake of certain fruits. This does not mean that you need to cut out all fruits and never ever eat a tropical fruit. You should just eat fewer tropical fruits and smaller portions of such fruits.

Diet and food scare stories: recognising them
A good rule of thumb to use when you receive scare stories per e-mail or if you have come across a website that uses scare tactics to condemn certain food products, is to check how many illnesses, diseases and aberrations this food product is supposed to cause.

If the list of diseases and problems goes on and on, you know that this is a typical scare story and not based on scientific fact. Certain foods can have negative effects, for example a person who is allergic to peanuts can die if exposed to peanuts, but no one food or food product is going to cause 10-15 diseases.

If you receive scary e-mails or read about foods that are ‘pure poison’ don’t take this advice to heart. Consider where it originated from and do some research of your own by visiting credible websites or speaking to experts. – (Dr Ingrid van Heerden, DietDoc)

Any questions? Ask DietDoc


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