Non-drug treatment of hypercholesterolaemia

The reason for treating hypercholesterolaemia is to reduce your risk of cardiovascular disease (CVD), rather than concern that your cholesterol levels should fall within narrow limits. The main treatment to reduce CVD risk is change of diet and lifestyle.

Other conditions, such as high blood pressure, may also need to be treated. If you are at high risk of CVD, you may need to take medication to lower blood cholesterol levels if dietary and lifestyle changes do not improve things sufficiently.

Lifestyle

Several lifestyle changes reduce the risk of CVD. These include stopping smoking, drinking alcohol in moderation, losing weight and increasing aerobic exercise.

Cigarette smoking

Cigarette smokers who give up smoking show a rapid fall in CVD risk (50 per cent in one year), although the level of risk does not approach that in people who have not smoked for many years. Giving up smoking is obviously difficult but can be helped by appropriate support. Nicotine patches or gum has a role, particularly in people who are highly motivated to quit. Quitting smoking doesn’t reduce blood cholesterol levels but high cholesterol levels are less likely to cause CHD in people who don’t smoke compared with those who do.

Alcohol consumption

The consequences of excessive alcohol intake are well known. In addition to the effects on social activities, there are clear medical risks, including permanent liver damage, obesity, hypertension and damage to the heart. High alcohol intake is also a risk factor for stroke.

However, there is considerable evidence of benefits from light-to-moderate alcohol consumption, including lower mortality, as a result of a reduced risk of CVD, particularly coronary heart disease (CHD). Benefits for women are found at lower levels of alcohol intake than for men and are most pronounced in postmenopausal women. This is not surprising because the incidence of CVD increases after the menopause, and therefore the absolute risk is higher in this age group than in younger women.

The main benefit therefore appears to result from alcohol itself, rather than from other components. Drinking moderate amounts of alcohol affects your cholesterol metabolism, raising your HDL-cholesterol levels. It is possible that alcohol protects through other mechanisms, such as preventing blood clotting and improving the state of your artery walls.

What is moderate alcohol consumption? The usual recommendations are that men should drink no more than 21 units of alcohol spread over the course of a week, and women no more than 14 units. One glass of wine, a pub single measure of spirits or half a pint of beer contains one unit.

Weight

The healthy weight range for people of different heights is worked out clinically using the body mass index (BMI) formula:
BMI = Weight (kg)/[Height × Height (m2)]
If this calculation gives a result between 18.5 and 24.9, you are in the healthy weight range for your height – this means that your weight is not increasing your risk of premature death, especially from CVD. If your BMI is less than 18.5, you are underweight and if it is 25 to 29.9 you are overweight. If it is 30 or above, you are classed as obese, and your risk of dying prematurely is double that of someone in the healthy weight range. These BMI calculations are widely used for all adults, although the ranges are slightly smaller for women.

Exercise

People who are physically active are less likely to develop CVD than those who are not. The good news is that the greatest benefit comes from being moderately active – the extra gain from vigorous or prolonged exercise regimes is small. Types of exercise that are beneficial include brisk walking, dancing or reasonably heavy gardening. The protective effect is lost if you stop exercising.

The reasons for the beneficial effects of exercise are not completely clear but probably include weight reduction, lower blood pressure and increasing your blood levels of HDL-cholesterol.

Dietary changes

The cholesterol in our circulation comes from two sources. Small amounts are obtained pre-formed from certain foods such as egg yolk and meat products, but most is made in your liver from saturated fats (animal and dairy fat), so a diet high in saturated fats raises blood cholesterol levels.

Changing your diet is therefore essential for reducing blood cholesterol levels, whatever their cause. There are two main dietary approaches:

• generally reducing the amount of fat that you eat
• using or avoiding specific foods or additives.

General dietary changes

You may need to change your diet to reduce your saturated fat intake but you may also need to adjust it so that you lose weight. Fat is the richest source of calories in your diet. On average in the UK, over 40 per cent of the calories in our food comes from fat.

Healthy eating guidelines for the general population recommend that fat should contribute less than 35 per cent of calories. This is reduced to less than 30 per cent for those at high risk from CVD, including people with hypercholesterolaemia. The general principles of the dietary approach to reducing cholesterol are outlined in the box on page 85.

Low-cholesterol diet

People often talk about a ‘low-cholesterol diet’. What they really mean is a cholesterol-lowering diet. ‘Low­cholesterol diet’ implies that reducing cholesterol intake is the objective of the diet.

Where does cholesterol come from?

Although the amount of cholesterol in your diet is important, it is probably less so than the amount of saturated fat that you eat, because most cholesterol in your body is made in the liver from dietary saturated fats.

Cholesterol is also absorbed rather poorly from the gut, with over half remaining behind. The main objective of changing your diet is to reduce your saturated fat intake. However, saturated fat and cholesterol tend to occur in high amounts in the same foods, so by avoiding fat you are probably also lowering your intake of cholesterol.

As the intake of saturated fats (animal and dairy fat) is more important than that of cholesterol, foods rich in cholesterol with a modest amount of saturated fats are allowed in moderation, including eggs and shellfish. It is OK to eat two eggs and one portion of shellfish per week.

The atherogenic index

The fat content of food is expressed here as an atherogenic index. This method of expressing fat content gives high values for foods rich in saturated fat (increases risk of CVD). The greater the proportion of unsaturated fat the lower the value (reduces risk of CVD).
 

Fibre

Dietary fibre, which consists of carbohydrates resistant to our digestive enzymes, is found in fruit, vegetables and wholegrain cereals. Fibre intake is associated with a protective effect against CVD.

One study in America followed 75,521 female nurses for 10 years, having established their intake of fibre before and during the period of investigation. The relationship of fibre intake to CVD was studied after adjusting the results for other factors that could affect the incidence of CVD, such as smoking, age, weight, alcohol intake, HRT usage, vitamin intake and exercise.

The nurses with the highest intake of wholegrains had the lowest incidence of CVD. These results have been confirmed in other studies. This protective effect is related to the effects of dietary fibre on the absorption of fats in the gut, resulting in lower LDL-cholesterol levels. Three grams of fibre per day in the form of oats can lower cholesterol by around 0.15 mmol/litre.

General principles of a cholesterol-lowering diet (high fibre)

• Lose weight if your weight is increased
• Remember that alcohol has lots of calories
• Eat plenty of fresh fruit and vegetables – at least
• five portions per day
• Limit red meat, eat more chicken and fish
• Use margarine made from stanol esters (see page 86), olive oil or one high in polyunsaturates
• Use skimmed or semi-skimmed milk
• Avoid lard; use olive oil or an oil that is high in polyunsaturated fats for cooking, for example, corn, sunflower or soya oil
• Include wholemeal bread, cereals, pasta and rice in your diet
• Cut down on all animal fats – they are rich in saturated fatty acids
• Animal and vegetable proteins have little effect on cholesterol levels
• You are allowed treats, including eggs, occasionally!

Fish and fish oils

There is strong evidence that people who eat fish are at lower risk of developing CVD than those who do not. This was first noticed in Greenland Eskimos who eat a diet with a very high fat content from seal, whale and fish, yet have a low incidence of CVD.

This is now known to be the result of a type of polyunsaturated fat, known as omega-3 fatty acids, of which two are found in fish oils: eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA). EPA and DHA are found in large amounts in fish and sea mammals, but are almost absent from land animals and plants because they are not produced by marine animals themselves, but by microscopic plankton that are at the base of the marine food chain.

Fish oils with high amounts of EPA and DHA, but with fat-soluble vitamins removed (which could be toxic in high doses), are available from health food shops. Untreated cod liver oil contains fat-soluble vitamins. It is unlikely that the major benefits of fish and fish oil result from their effect on blood lipids – they have little effect on cholesterol, although they do reduce blood triglyceride levels. However, they have a number of anti-clotting effects and help to prevent abnormal heart rhythms developing. Fish oils also improve the health of the walls of arteries and lessen atherosclerotic plaque formation.

It used to be thought that fish and fish oils should not be increased in patients with diabetes because they could make diabetes more difficult to control. This is now thought not to be the case, provided that the total number of calories is not increased.

Specific foods and additives

Foods obviously contain essential nutrients, but they also contain substances that are not nutrients but have properties that are potentially useful. Less attention has been paid to the effect of individual foods on blood cholesterol and the risk of CVD than to fat intake.

The notion that natural remedies, such as specific foods or drinks, can lessen CVD risk is extremely attractive. However, it is equally possible that a relatively high intake of specific foodstuffs could be harmful – remember the effect of saturated fatty acids. Specific foodstuffs and natural remedies should be assessed as rigorously as drugs.

Margarine containing stanol esters

Cholesterol is a sterol and similar compounds with slightly different structures are found in plants. As they have a similar structure, plant sterols, particularly a group called stanol esters, can interfere with the absorption of cholesterol.

Stanol esters such as sitostanol have been used in a chemically modified form in mayonnaises or margarines, such as Benecol and Flora pro.activ. Several clinical studies have shown that this type of margarine lowers blood cholesterol levels. For example, a study in people with mildly elevated blood cholesterol levels showed that it lowers the total cholesterol level by around 10 per cent when used in relatively small amounts of three grams a day. Very little stanol is absorbed into the body and the major effect appears to be by reducing cholesterol absorption from the gut. Stanol­containing yoghurts and drinks are now available.

Antioxidants

These are of interest because chemical change in LDL by a process called oxidation increases the uptake of LDL particles by scavenger cells in arterial walls, forming the basis of atherosclerotic lesions. Antioxidants prevent these changes in LDL, at least in the laboratory.

Dietary antioxidants include vitamins A, C and E, and polyphenols. Garlic also has antioxidant properties (see below). There are two points about dietary antioxidants to consider:

• whether the amount in the natural diet affects CVD risk
• whether the addition of antioxidant dietary supplements has any benefit.

Observational studies relating vitamin E or vitamin C intake to CVD are contradictory, with some suggesting benefit and some not. Studies in which high doses of vitamin E or beta-carotene (one form of vitamin A) were added to the diet have been disappointing.

In addition to studying statins (see page 70), the Heart Protection Study also looked at whether vitamin E supplements prevented heart attacks. There was no benefit at all from the extra vitamin.

Polyphenols are a type of antioxidant found in drinks such as black or green tea and red wine. The beneficial effects of red wine seem to be shared with other alcoholic drinks that do not have high contents of polyphenols. So far there is not enough known about the effects of polyphenols but studies are being made of plant extracts given to animals and the early results are encouraging, although it is too early to recommend them for human use.

Some metals, particularly copper, manganese, zinc and selenium, are involved in antioxidant processes within the body. Only small amounts of these are required in a healthy diet – this is why they are called trace metals. There is no clinical evidence that dietary supplements of these trace metals are of any value in preventing CVD.

Overall, the case for dietary antioxidants is unproven.

Garlic

Some people believe that garlic may be useful in reducing the risk of CVD through an effect on cardiovascular risk factors. There are several reasons for this, one of which is that garlic consumption is high in areas where the risk of CVD is low. This doesn’t prove that garlic is protective because other factors are also different in these areas, such as a low intake of saturated fat in the diet.

Garlic has several properties that may be beneficial. These include reducing the tendency for blood to clot, reducing blood pressure and lowering levels of fats in blood. In addition, garlic has antioxidant activity.

Some articles in the medical literature suggest that a powder prepared from garlic lowers cholesterol, although two recent high-quality studies do not confirm this. These are important because they include more participants than previous investigations. If trials are added together, the overall effect is small, a reduction of 0.1 mmol.

We do not yet have enough information on the other possible effects of garlic, such as on blood clotting or through antioxidant activity, to judge its possible benefit. In addition, garlic has not been investigated to see whether it reduces the incidence of heart attacks. The present situation is therefore that there is no proven benefit from eating garlic to prevent CVD.

Avocadoes

Avocadoes are rich in monounsaturated fatty acids and avocado oil has a composition closely resembling that of olive oil. They contain no cholesterol. Avocadoes are therefore thought to be beneficial in a diet to prevent CVD.

Coffee

There has been considerable controversy about the effect of coffee on blood lipids and, in particular, cholesterol levels. The effect appears to relate to the type of coffee beans and the method used to prepare the drink.

Blood cholesterol levels are about 15 per cent higher in men who drink 10 or more cups of coffee a day, made by boiling beans, compared with non-coffee drinkers. The substances responsible are cafestol and kahweol, which are from a group of chemicals called diterpenes.

The types of brew that have a cholesterol-raising effect are Turkish coffee, Scandinavian boiled coffee and cafetière coffee. The effect is not seen in those who drink instant or filtered coffee. It seems sensible to avoid drinking lots of boiled coffee, although it is unlikely that an occasional cup of cafetière coffee will do much harm.

Herbal remedies

There is a great deal of interest in herbal remedies such as hawthorn extracts, red yeast rice, guggul, fenugreek and artichoke. Some of these, particularly fenugreek seeds, do appear to have cholesterol-lowering properties, although there is no evidence of benefit, in terms of a reduced incidence of CVD.

Vitamins

Vitamins A and E have been discussed above. There is some evidence that patients with low blood levels of folate (a type of vitamin B) have a greater risk of CVD than those with higher levels. Rich dietary sources of folate are breakfast cereals, fruit, green vegetables and beans (legumes). It is difficult to know, however, whether folate has an independent effect on blood cholesterol levels or whether it is a marker for some other component of diet, such as fibre.

There is a further factor that may be important in relation to folate. High blood levels of the amino acid, homocysteine, appear to damage artery walls, increasing the risk of arterial disease. Folate reduces homocysteine in blood and high folate concentrations could protect against arterial disease by this mechanism. However, for the present, this is speculation.

Grapefruit

Grapefruit is unique among fruit and vegetables in increasing blood levels of many drugs, which increases their potency. This effect occurs because grapefruit (and grapefruit juice) contains a substance or substances that slow the removal of drugs from the body by the liver.

In addition, there is the possibility of interactions with prescribed drugs and side effects have been described, including abdominal upsets and low blood potassium levels.

The best advice is to avoid grapefruit and grapefruit juice if you are taking any of the drugs affected, which includes statins (see box). Countries that include grapefruit warnings on labels include New Zealand, Australia and the Netherlands. It is possible that there are more grapefruit–drug interactions that are not yet recognised.

Some drugs that carry a grapefruit interaction warning:

• Sedatives (alprazolam, midazolam)
• Cholesterol-lowering drugs (statins)
• Drugs used in the treatment of angina and hypertension (amlodipine, nifedipine, verapamil)
• Oral contraceptive components (ethinylestradiol)
• Antidepressants (clomipramine)
• Others (ciclosporin, tacrolimus)

Specific diets

Specific diets, such as the Atkins and GI diets, often receive considerable publicity. The Atkins diet is low in carbohydrate and high in fat and, on this basis, cannot be recommended.

The abbreviation GI stands for glycaemic (or sugar) index and is a measure of the amount that the blood sugar level rises after eating that food. Bread and sugar have an index of 100, whereas the value for baked beans is 69 and for an apple 52. There is no evidence that low GI diets have any effect on blood cholesterol levels.

Professional dietary advice

Should you see a dietitian? Dietitians are very knowledgeable about the right and wrong sorts of food to eat. They are better than doctors at lowering blood cholesterol through dietary advice although similar reductions can be achieved using self-help resources, if the basic principles are understood.

KEY POINTS

• The main treatment to reduce CHD risk is change of diet and lifestyle

• Diet is the cornerstone of treatment to reduce blood cholesterol levels

• Stop smoking

• Drink alcohol in moderation

• Maintain a healthy body weight

• Take regular exercise

• Reduce the amount of animal and dairy fat that you eat