Position statement on the dietary management of people with dyslipidaemia
Association for Dietetics in Southern Africa (ADSA)
This position statement is based on the scientific information summarised in The Effect of Diet on Lipid Metabolism: Technical Report, 1999. 1

S A J Clin Nutr 2000 February Vol. 13 No 1

Introduction
Dietary intervention should always be the first step in the treatment of hypercholesterolaemia, whether hypercholes-terolaemia is ascribed to genetic or environmental factors. In South Africa many people suffer from high blood cholesterol concentrations and for them dietary treatment forms an integral part of the management of dyslipidaemia. It is recommended that persons with dyslipidaemia, but without coronary heart disease (CHD) or with multiple risk factors for CHD, receive dietary treatment for a minimum period of 4 weeks to 3 months before drug treatment is introduced.2

Aim
The aim of these dietary guidelines is to ensure uniform dietary treatment of South Africans with dyslipidaemia. These guidelines apply to adults and children over the age of 2 years.

Cultural, ethnic, regional and religious differences in dietary practices and food choices of South Africans exist. However,despite these differences, food choices should be of such a nature that they will still meet these dietary guidelines.

Objectives

• To achieve and maintain optimal plasma lipid and lipoprotein concentrations.
• To achieve and maintain appropriate body weight by balancing energy intake and energy expenditure.
• To consume those nutrients which influence plasma lipids and lipoproteins positively and decrease those which have a negative effect.
• To ensure optimal nutrition for the individual with dyslipidaemia.

Energy
Energy requirements depend on sex, age and energy expenditure. Enough energy should be provided from a variety of foods to ensure the maintenance of a desirable body weight. In children and adolescents enough energy should be provided for growth and development.

Table I serves as a guideline for the energy requirements of an adult based on weight and activity level.3 The Recommended Dietary Allowances 4 (1989) should be consulted for more information on the energy requirements of children, but the following guideline can be used: children 4 - 6 years of age 377 kJ/kg; and children 7 - 10 years of age 293 kJ/kg.

A body mass index (BMI) of > 19 and < 25 is recommended for an adult (BMI = mass in kg/height in m2 ).

Table I. Guideline for energy requirements based on body weight and level of activity 3

Total fat
In most adults at least 15% of energy (15%E) should come from fat, while women of reproductive age need at least 20%E from fat.5 Many South African adults have a fat intake in excess of 30%E.6

A total fat intake of less than 30%E or approximately 33 g fat/4 200 kJ (the Step 1 diet) is recommended for adults with moderate-risk hypercholesterolaemia. A fat intake of 25%E (28 g fat/4 200 kJ), the Step 2 diet, is recommended for those with moderate-risk hypercholesterolaemia, in addition to two other risk factors, or high-risk hypercholesterolaemia. Only for those individuals with very-high-risk hypercholesterolaemia, a fat intake of 20%E could be considered (Step 3 diet). A diet which is very low in fat and high in carbohydrate might increase triglyceride (TG) levels and lower high-density lipoprotein cholesterol (HDL-C) levels.7 Consult Table II for a summary of the composition of the different diets for the treatment of dyslipidaemia.

For children under 2 years of age, a fat intake of 30 - 40%E (34 - 45 g/4 200 kJ) is recommended.5 Breast-milk provides between 50% and 60%E from fat and during weaning fat intake should not fall rapidly.

Although a low-fat diet is recommended, a very-low-fat diet (10%E) reduces not only low-density lipoprotein cholesterol (LDL-C) but also HDL-C 8 and tends to increase TG concentrations.9 A moderated fat intake of 25 - 30%E, which is more palatable, is recommended because it will ensure better compliance with the dietary prescription.

Table II. Energy and nutrient goals of the Step 1, 2 and 3 diets for the treatment of hypercholesterolaemia and hypertriglyceridaemia

Saturated fatty acids
There is little doubt that saturated fatty acids (SFAs) increase plasma cholesterol concentrations,9-12 and SFA intake should therefore be reduced to < 10%E (11 g/4 200 kJ) for those with moderate-risk hypercholesterolaemia (Step 1 diet), and to < 7% (7g/4 200 kJ) for those with high-risk hypercholesterolaemia (Step 2 diet).13 The SFAs that have a cholesterol-elevating effect are lauric (C12:0), myristic (14:0) and palmitic (16:0) acids,10-12 but stearic acid (C18:0) does not raise plasma total cholesterol (TC).14-16 Animal fat, palm kernel oil, palm oil and coconut oil are important sources of the cholesterol-elevating SFAs in the diet and should be avoided as far as possible.

Trans fatty acids
Trans fatty acids should be regarded as SFAs and should therefore be restricted.17-20 Foods typically high in trans fatty acids are hydrogenated vegetable fats, e.g. some brick margarines, cooking fat and foods prepared with these hydrogenated vegetable and marine oils.

Mono-unsaturated fatty acids
Mono-unsaturated fatty acids (MUFAs)21-24 are regarded as neutral and only cholesterol-lowering when they replace SFAs in the diet.16, 25 A deliberate increase of MUFA intake without taking total fat intake into account should be avoided. A MUFA intake of ±15%E or 17 g/4 200 kJ is recommended. Products which could be used to increase MUFA intake at the expense of SFA are olive oil, canola oil and soft-type tub margarines, e.g. olive oil- or canola oil-based margarines, and avocado.

Polysaturated fatty acids
Since no long-term studies have demonstrated the safety of a high intake of polyunsaturated fatty acids (PUFAs) and the intake of large amounts of PUFAs may lower HDL-C, the intake of PUFAs should not be higher than 10%E or ±11 g/ 4 200 kJ. There are two families of PUFAs in the diet, the omega six (n-6), of which linoleic acid is the parent fatty acid, and the n-3 PUFAs, of which a-linolenic acid is the parent fatty acid. Both these fatty acids are essential and therefore important in the diet. Important sources of n-6 PUFA are plant oils such as sunflower oil, while fish (especially fatty fish), legumes and green leafy vegetables are good sources of n-3 PUFAs.

To meet the needs of essential fatty acids, an intake of 1 - 3%E or 1 - 3 g/4 200 kJ from linoleic acid is recommended.26 Should dietary fat contribute less than 25%E to the diet, a higher percentage of energy should come from linoleic acid in order to prevent the diet from being deficient in essential fatty acids. In adults the requirement for linoleic acid will be met by the daily inclusion of approximately 15 g of sunflower oil or 20 g of margarine high in PUFAs. Sunflower oil and the soft-type tub margarine high in PUFAs are recommended instead of brick margarine, cooking fat and butter.

An n-3 PUFA intake of at least 0.5%E (0.6 g/4 200 kJ) per day is recommended.27 In the diet the ratio of linoleic acid (C18:2n-6) to a-linolenic acid (C18:3n-3) should be between 5:1 and 10:1. More n-3-rich food, e.g. green leafy vegetables, legumes and fish (especially fatty fish), is recommended for those with a ratio > 10:1. 5 The n-3 PUFAs lower TG concentrations significantly and have a beneficial effect on blood clotting, probably through inhibition of platelet aggregation. 28,29,30 Total cholesterol is virtually unaffected by n-3 PUFAs, while the effect on HDL-C is negligible.31 The n-3 PUFAs tend to increase LDL-C in normoTG but especially in hyperTG individuals.31 Fish oil supplements for the treatment of hyperTG concentrations should only be used under the supervision of a medical doctor or dietician. Since n-3 PUFAs tend to increase LDL-C, fish oil supplements should be used with caution in those with elevated LDL-C concentrations.28,29,31,32

Food with a high PUFA content should contain at least 0.6 mg tocopherol equivalents per gram of PUFA to stabilise the unsaturated fatty acid.5 If foods contain a high amount of fat, with fatty acids containing more than two double bonds, e.g. foods which contain linolenic acid (C18:3n-6) or fatty fish, more tocopherol may be necessary.5

Dietary cholesterol
The response to dietary cholesterol intake varies in individuals because it may be influenced by the degree of absorption in the intestine, bile acid synthesis, cholesterol turnover, hypo- and hyper-responders and the apo E phenotypes.33-37 It is recommended that the daily intake of dietary cholesterol be restricted to less than 300 mg or 100 mg/4 200 kJ (Step 1 diet) in persons with hypercholesterolaemia. A cholesterol intake of 200 to 250 mg/day is recommended on the Step 2 diet, and 100 to 150 mg/day on the Step 3 diet. All animal foods contain dietary cholesterol and contribute to the cholesterol intake. When recommending the use of foods such as eggs, liver and organ meats it should be acknowledged that these foods may be important affordable sources of protein in the diets of people with low incomes. Legumes are also a good source of protein and low in cost and their intake should be encouraged.

Carbohydrate
A carbohydrate intake of 55 - 60%E (136 g-148 g/4 200 kJ) from a variety of sources, e.g. grains, cereals, fruit and vegetables, is recommended.An increase in carbohydrate intake may raise TG levels, especially in the short term.38-40 More fibre in the diet may, however, counteract the negative effect of a high-carbohydrate diet on TG levels 41 and emphasis on the intake of complex carbohydrate is advised.

Sugar
Sugar forms part of total carbohydrate intake. When TG concentrations are elevated, a sugar intake of £10%E (25 g/ 4 200 kJ) is recommended. Scientists are of the opinion that if intake of sucrose and other refined sugar is restricted to 10%E there is, in general, no danger of hyperTG except in rare cases.42 In severe hyperTG, sucrose intake can be restricted further.43 An intake of 10%E from sugar will probably not affect total cholesterol concentrations.

Dietary fibre
Soluble fibre (e.g. pectin, guar gum, oat bran and psyllium) and dry beans have moderate cholesterol-lowering effects.44-48 Although consensus on the desirable daily fibre intake has not been reached, an intake of approximately 25 - 35 g/day or 13 g/4 200 kJ can be recommended for adults.49 Food sources high in water-soluble fibre, e.g. oat bran, legumes (especially dry beans), cereals, fruit and vegetables, should make up 30 -40% of the total fibre intake.50 For children older than 2 years of age an amount equal to or greater than their age plus 5 g per day is recommended.49 When fibre is added to the diet its intake should be increased gradually and accompanied by adequate fluid intake.

An unrealistic high intake of dietary fibre may have gastro-intestinal side-effects and may interfere with the absorption of nutrients such as calcium.13

Protein
A protein intake of approximately 15%E (37 g/4 200 kJ) is recommended. Should energy intake be low (< 5 000 kJ) an intake of 20%E is advised in order to meet the Recommended Dietary Allowance (RDA) for protein and the recommendation of 0.8 g protein per kilogram body weight.4 Protein should come from animal as well as vegetable sources.

Alcohol
One to two alcoholic drinks per day are allowed for those who consume alcohol.27, 51-53 The alcohol allowance should not be accumulated for the weekend.

The dietary guideline for alcohol intake serves as a guideline for those who consume alcohol on a regular basis and is not intended to encourage those who do not drink to consume alcohol regularly.19

Pregnant and lactating women should be advised not to consume alcoholic drinks.54 The consumption of alcohol is also not advised for persons with a family history of alcoholism, hyperTG, pancreatitis, liver disease, heart failure or uncontrolled hypertension, and for those on medication that interacts with alcohol.53 Since alcohol is high in energy and oxidised to fat, persons with a weight problem should restrict alcohol intake.

One alcoholic drink is defined as the equivalent of 10 - 12 g alcohol; beer = 340 ml; dry or semisweet wine = 120 ml; fortified wine = 60 ml; brandy = 25 ml; whisky = 25 ml; other spirits = 25 ml; liqueur = 25 ml.

Antioxidants
Antioxidant supplementation is not recommended. At present more research is needed before the use of supplements can be considered.55-59 A food-based approach is recommended for the intake of adequate antioxidants and five portions of vegetables and fruit (including a dark green or yellow and vitamin C-rich portion) per day is recommended to provide the necessary antioxidants.

In view of the large number of people who use supplements currently, the following recommendations can serve as a guideline for the safe use of antioxidant dietary supplements: vitamin E 200 IU/day; b-carotene 15 - 50 mg/day; vitamin C a minimum of 50 mg/day; selenium a maximum of 200 µg/day.60 However, more research is needed before it can be stated that these dosages will prevent atherosclerosis, or whether larger dosages are required, or whether their use has any adverse effects.60 The effect of vitamin E supplementation on the bleeding time of subjects consuming anticoagulants is not clear at this stage.

Vitamin B supplements
There are still questions about hyperhomocysteinaemia as a risk factor for CHD.61 Vitamin supplementation may be necessary to treat hyperhomocysteinaemia 62,63 and Ubbink et al.64 recommend that the treatment of moderate hyperhomocysteinaemia includes a prudent diet as well as appropriate vitamin supplementation for at least 6 weeks. Treatment of moderate hyperhomocysteinaemia is effective when using a combination of 1.0 mg folic acid, 400 µg vitamin B12 and 10 mg pyridoxine for at least 6 weeks.64 The consumption of foods fortified with these vitamins could be encouraged. When vitamin supplementation is discontinued patients should be monitored to establish whether dietary vitamin intake is sufficient to maintain plasma homocysteine concentrations within the reference range.

Coffee
The association between coffee intake and CHD is not ascribed to the caffeine content of coffee.65 The cholesterol-raising effect of coffee depends on diterpenes which vary according to the method of preparation. Unfiltered coffees such as boiled, Turkish/Greek and cafetiére (French press) coffee contain cafestol and kahweol, mainly present as fatty esters but also as small amounts of free alcohol, which have a cholesterol-raising effect.66,67 Chronic consumption of five or more cups of these types of coffee is not recommended for people with elevated cholesterol levels.67 The lipid-rich fractions in coffee do not pass through filter paper and are therefore not found in filter coffee.68,69 Instant, percolated and filtered coffee contains little or no cafestol and kahweol and no specific guideline for the limitation of their intake is given in terms of the cholesterol-elevating effect of coffee.

Coffee is, however, also an important source of caffeine, which may have an effect on hypertension. It is recommended that the intake of caffeine from all sources is restricted to the equivalent of not more than 4 cups of caffeine-containing coffee per day.27

Hypertension
Hypertension is also one of the major risk factors for CHD, and in addition to the maintenance of a desirable body weight guidelines on the following nutrients are also important for individuals with dyslipidaemia:

Sodium
Asodium intake of £ 3 g sodium (5 g sodium chloride/5 g salt) per day is recommended. Sodium chloride may be more harmful than sodium alone or in combination with other anions.27,70 Attention should therefore specifically be given to the intake of sodium chloride. Foods high in salt and those containing flavouring salts should be limited in the diet. Emphasis on the use of iodated salt should not encourage the use of more salt.

Other minerals
Although there are indications that an increase in the intake of potassium,71,72 calcium 73,74 and magnesium 71,72 may be beneficial, it is not possible at this stage to formulate a specific recommendation for these minerals, other than to meet the RDA. The intake of a variety of five portions of fruit and vegetables is, however, recommended. The use of potassium salts could only be considered as a replacement for sodium chloride under medical supervision.

Popular beliefs

Polyphenols
At present there are no specific guidelines regarding the intake of flavonoids. In the Western diet quercetin is the major flavonol.75 Flavonoids are known as polyphenols and have antioxidant properties and are found in tea, onions, broccoli, red grapes, cherries and apples.75 The antioxidant properties of tea are probably lost when milk is added to the tea.76 Red wine also contains phenolic substances which have potent antioxidant properties.77 More research is needed to answer the question of whether antioxidant flavonoids are protective against atherosclerosis 78 and what level of intake may have a beneficial effect.

Plant sterols
Dietary plant sterols, especially sitostanol, have a cholesterol lowering effect because it is suggested that sitostanol inhibits the absorption of cholesterol.79 Studies have shown that the use of sitostanol-ester margarine (1.8 - ± 3.0 g sitostanol/day), as part of the total daily dietary fat intake, has a serum total cholesterol- and LDL-C-lowering effect.80,81 There is, however, an indication that the effect of sitostanol may be diminished when the diet is low in cholesterol.82 Margarines enriched with sitostanol are not commonly available in South Africa.

Garlic
There is currently insufficient evidence to recommend garlic therapy in clinical use for lipid-lowering benefits, though data do indicate that supplementation over a few months may have positive results.83,84 Further research is needed before recommendations can be made with respect to garlic supplementation, but garlic can be included in a varied diet adhering to general prudent dietary principles.

Lecithin
Because of controversial results regarding the effect of lecithin on lipoprotein levels, poor study designs, and data analysis errors in most of the studies, supplementation with lecithin is not recommended.85

Meal frequency
Divide daily food intake into 3 to 6 meal occasions per day. Encourage the use of fruit and high-fibre, low-fat grains as snack foods.

Labelling
Individuals with dyslipidaemia should be encouraged to read food labels and, where possible, to choose foods that are low in energy, total fat, saturated fatty acids, hydrogenated plant fats and marine oil, cholesterol, salt and flavouring salts. Products endorsed by health organisations should not be consumed ad libitum. The food industry should be encouraged through food labelling legislation to declare the type and amount of fat in their products.

Lifestyle

Smoking
Smoking is a major risk factor for CHD and the individual with dyslipidaemia is advised not to smoke.

Physical activity
Regular moderate exercise should be encouraged since this will aid any weight loss required and may also improve the lipid profile by an increase in HDLand a reduction in TG. Physical activity is recommended for the individual with dyslipidaemia, but only in consultation with their physician.

Patient counselling
The individual with dyslipidaemia should preferably be referred to a registered dietician for high-quality, high-intensity dietary intervention. Dieticians are encouraged to follow a quantitative approach, especially in the high-risk individual. The individual with hyperTG needs specialised dietary intervention and should be referred to a lipid clinic. An initial intervention visit should be succeeded by follow-up visits to ensure long-term compliance with the dietary guidelines.

Practical adaptation of the habitual dietary intake of the individual with dyslipidaemia to meet these guidelines forms the basis of the successful dietary management of dyslipidaemia. This can only be achieved by close co-operation between the individual with dyslipidaemia and the dietician.

Practical guidelines
Practical guidelines for the treatment of dyslipidaemia are summarised in the South African Medical Association’s Clinical Guideline, ‘Dietary management of people with dyslipidaemia’.86

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Last updated: 17-Feb-2004