If you are reading this before breakfast, please consider having an egg. Any day now, the US government will officially accept the advice to drop cholesterol from its list of “nutrients of concern” altogether. It wants also to “de-emphasise” saturated fat, given “the lack of evidence connecting it with cardiovascular disease”.
This is a mighty U-turn, albeit hedged about in caveats, and long overdue. The evidence has been building for years that eating cholesterol does not cause high blood cholesterol. A 2013 review by the American Heart Association and the American College of Cardiology found “no appreciable relationship between consumption of dietary cholesterol and serum [blood] cholesterol”.
Cholesterol is not some vile poison but an essential ingredient of life, which makes animal cell membranes flexible and is the raw material for making hormones, like testosterone and oestrogen. Your liver manufactures most of the cholesterol found in your blood from scratch, and adjusts for what you ingest, which is why diet does not determine blood cholesterol levels. Lowering blood cholesterol by changing diet is all but impossible.
Nor is there any good evidence that high blood cholesterol causes atherosclerosis, coronary heart disease or shorter life. It is not even a risk factor in people who have already had heart attacks. In elderly people — ie, those who have the most heart attacks — the lower your blood cholesterol, the greater your risk of death. Likewise in children.
Indeed, the evidence that insisting on low-fat diets caused people to eat more carbohydrates, and that led to the explosion in obesity and diabetes, looks pretty strong — so far. After all, the main route by which the body lays down fat is to manufacture it from excess sugar in the liver. But why did carbohydrate consumption start to increase so rapidly in the 1960s? At least partly because of the advice to avoid meat and cheese. Obesity and diabetes are the price we have paid for getting fat and cholesterol so wrong.