When I qualified as a doctor, cholesterol was way down my list of priorities - and I'm not sure I even knew there was more than one kind. These days, when August rolls around and my keen new trainee arrives, I know it's going to be one of the first subjects they ask me to teach them about. Because with about seven million Britons on statins - up from about 58,000 in 1992 - every patient has heard of cholesterol.
If you've had a heart attack, stroke or type 2 diabetes you'll almost certainly be advised to take statins. The evidence for benefit in this sort of patient is overwhelming - every 1 mmol/L reduction in LDL cholesterol cuts the risk of dying from heart attack by 19%, the risk of heart attack or dying from heart attack by 23%, the risk of stroke by 17% and the risk of dying by 12% (ref 1). In a study of nearly 3,000 people with type 2 diabetes who hadn't had a heart attack, a daily statin cut the risk of major cardiovascular events by 37% (ref 2).
But in more recent years, more and more people who don't have one of these conditions have been given statins. Many studies suggest they can cut your risk of heart attack or stroke even if you haven't had one. However, like all drugs, statins cause side effects for some people so they're mostly given to people at higher risk of heart disease. Your risk of heart attack and stroke is calculated using a formula that includes your age, gender, smoking status, cholesterol and HDL ('good') cholesterol levels etc. If you're over 40, you're entitled to a 5-yearly NHS Health check to work out your risks - or you can get one from many pharmacists. For instance, over 300 branches of Lloyds offer heart disease risks assessments, and some offer them free as part of the NHS programme.
Until a year ago, the UK recommendation was that anyone with a 10-year risk over 20% should be offered a statin - a year ago, it changed to 10%. But many people on the borderline of being 'high risk' could come out of this category with lifestyle changes.
Losing weight has clear benefits for cholesterol, blood pressure and type 2 diabetes risk - but most changes to your diet don't make that much difference on their own. So a 'portfolio diet', combining lots of beneficial changes, was devised. The Portfolio diet isn't new - the first study on it was published 13 years ago. But sticking to the original version could be tough. It included:
- A low-fat diet, with ≤7% of daily energy intake from saturated fat
- 5-10 daily servings of fruit and vegetables
- A vegetarian diet with no meat, egg yolks or milk products
- About 20 g/day of viscous (soluble) fibre (see below)
- 45 g/day of soya protein (mainly soya milk and soya meat substitute products in the trial) (see below)
- 2 g/day of plant sterols (the trial used plant sterol enriched margarine, equivalent to Flora Pro-Activ® in the UK, which provides 1.7 g in 1 tablespoon - you can get some from 'normal' foods but, for instance, you'd have to eat about 14 avocadoes a day to get 2 g)
- 46 g/day almonds (about 40 whole almonds).
Dietary sources of soluble fibre
- Oats (1 cup cooked oats contains about 4 g)
- Strawberries/apples/oranges/prunes (1 serving provides about 2.5 g)
- Rye (eg rye bread)
- Barley (can be added to stews and casseroles)
- Beans, peas and lentils (1 cup of cooked beans contains about 6 g)
Dietary sources of soya (preferably calcium-fortified)
- Soya milk/yoghurt/other dairy food substitutes
- Soya desserts
- Soya snack bars
- Soya mince
- Soya beans (substituted for peas and other vegetables).
There's no question that it works for many people if they stick to it - after a month, it reduced LDL cholesterol by an average of over 29% (3). But after a year, one in six people had dropped out and many others weren't sticking rigorously to the diet. A third had cholesterol at least 20% lower than when they started, but the mean drop in LDL cholesterol was down to 12.7% (4).
So how can you devise a portfolio that works for you? Each of these elements works on its own - 15 g soya a day could drop cholesterol by up to 6% a day (5); 30-35 g nuts by 5% (5); 2g plant sterols by 7-10% (5). You might consider a supplement such as Arterin®, containing red yeast rice (a natural product which works in a similar way to a statin), which can reduce LDL cholesterol by about 22% (6) - although you shouldn't take this if you're already on a statin or if you have liver or kidney problems.
Whatever way you choose, make sure you stick to it. We're all at risk of heart attack - it's just a question of how high that risk is. By making healthy lifestyle changes, we can all benefit.
1) Cholesterol Treatment Trialists' (CTT) Collaborators. Lancet 2005; 366 (9493): 1267-1278.
2) Colhoun H, Betteridge D, Durrington P, et al on behalf of the CARDS Investigators. Primary prevention of cardiovascular disease with atorvastatin in type 2 diabetes in the collaborative atorvastatin diabetes study (CARDS): multicentre randomised placebo-controlled trial. Lancet 2004;364:685- 96
3) Jenkins DJ, Kendall CW, Faulkner D et al. A dietary portfolio approach to cholesterol reduction: combined effects of plant sterols, vegetable proteins, and viscous fibers in hypercholesterolemia. Metabolism 2002; 51: 1596-604
4) Jenkins DJ, Kendall CW, Faulkner D et al. Assessment of longer-term effects of a dietary portfolio of cholesterol-lowering foods in hypercholesterolemia. Am J Clin Nutr 2006; 83: 582-91.
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