YOU HAVE no doubt heard the joke about the Corn Flakes packetbeing better for you than its contents. Well, Corn Flakes may stilltaste like sweetened cardboard, but new research suggests that thenation's favourite breakfast cereal could have a key role to play inpreventing its most common cause of death - heart disease.
This is definitely not another wacky health story in the 'sharkcartilage cures cancer' tradition. This time the science is seriousand, if the direction of current research is confirmed, theimplications for the Government's food policy could be huge. The keyto it all is a B vitamin called folic acid, until now best known forits ability to prevent neural tube defects such as spina bifida whentaken as a supplement by women before and during pregnancy.
Kellogg's now sprays liquid, synthetic folic acid on to its CornFlakes, Rice Krispies and Special K cereals. The exciting aspect ofthis otherwise less than appetising stage in the manufacturingprocess is that folic acid can reduce the blood level of a substancecalled homocysteine. This matters because high homocysteine countsare known to be closely associated with an increased risk of heartdisease.Homocysteine is an amino acid produced naturally in the body whenprotein is metabolised. The idea that it could be linked to heartdisease first emerged when Dr Kilmer McCully, a pathologist at theVeterans Affairs Medical Center in Rhode Island, investigated thecause of arterial disease and strokes in children with a rarecondition known as homocystinuria. Because of a genetic defect,such children are unable to dispose of homocysteine normally andtherefore have high levels in their blood.McCully suggested that a similar process might also be occurringin the general population of adults, not because of any genetic errorbut because inadequate intakes of folic acid were allowinghomocysteine levels to rise too high, become toxic and start damagingartery walls.Heart disease is in fact much more closely associated with highhomocysteine levels than with cholesterol. 'Levels of bloodhomocysteine greater than 14 micromoles per litre are associated withincreased risk of arteriosclerosis and the higher the homocysteinelevel, the higher the risk,' suggests Dr McCully. His analysis hasnow been confirmed by many studies, including the European ConcertedAction Project, which found that those people with the highesthomocysteine levels were as likely to develop vascular disease assomeone smoking 20 cigarettes a day.While a relationship between homocysteine and heart disease is nowwidely accepted, there are still doubts about whether elevatedhomocysteine levels are the direct cause of the problem. It could bethat the amino acid is just a marker for some other, still unknownfactor that is the real cause of the greater risk.'Homocysteine is an enigma in relation to cardiovascular diseaseand nobody yet knows for sure the mechanism linking the two,' arguesDr Jacob Selhub, director of the vitamin laboratory at TuftsUniversity, Boston. There have also, as yet, been no long-term,large-scale clinical trials to show that increasing people's intakeof folic acid will reduce their risk of developing heart disease.But there is little doubt that consuming more folic acid reduceshomocysteine levels. A recent study at Leeds University suggeststhat merely eating a bowl of breakfast cereal fortified with 200mg offolic acid every day for 24 weeks lowers the level by 10 per cent.Dr McCully considers a total daily folic acid intake of 350-400mgto be ideal. (400mg is the level recommended for women who aretrying to conceive, and those in up to 12 weeks of pregnancy). Butit is difficult to obtain this amount from food, partly because'natural' folic acid is easily lost during both cooking anddigestion. Synthetic folic acid is, surprisingly, a far bettersource, since almost all of it is absorbed by the body. So the bestsources of folic acid are vitamin supplements and vitamin-enrichedfoods, such as Corn Flakes.Since 1 January 1998, the US Food and Drug Administration (FDA)has required enriched grain products, including breakfast cereals, tobe fortified with folic acid at a level that should give the averagewoman an extra 100mg a day. The FDA's decision was undoubtedly alsoinfluenced by the emerging evidence on heart disease. But there areno similar plans for the UK, and those food manufacturers now addingfolic acid are doing so voluntarily.Each year, more than 145,000 people in the UK die of heart diseaseand the illness costs the health service almost pounds 4bn. Eventhough not even the most ardent advocate of folic acid claims itconstitutes a 'magic bullet' for heart disease, if the evidence forits effectiveness hardens, pressure on the Government to follow theFDA's lead will undoubtedly grow. The calls for mandatory foodfortification will intensify still further if tentative new evidencelinking homocysteine with Alzheimer's disease is also strengthened byfurther research. In time, a bowl of cereal could well help us snap,crackle and pop for many years to come.
