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Diet and Nutrition Prevention of Chronic Diseases

7. Cardiovascular diseases

  • 7.1 Are cardiovascular diseases a growing problem?
  • 7.2 How can diet and physical activity affect cardiovascular diseases?
  • 7.3 What nutrients are known to affect cardiovascular diseases?
  • 7.4 What food items are known to affect cardiovascular diseases?
  • 7.5 How could cardiovascular diseases be prevented?

7.1 Are cardiovascular diseases a growing problem?

stethoscope
Stethoscope
© Micro Application

Significant lifestyle changes in the second half of the 20th century have greatly contributed to the emerging epidemic of chronic diseases such as cardiovascular diseases (CVD).

Currently, 15.3 million people are estimated to die from cardiovascular diseases every year; that represents one-third of all global deaths from all causes. In the next two decades, the increasing burden of cardiovascular diseases will be borne mostly by developing countries.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.4.1 Background – 5.4.2 Trends 

They include amongst others:

  • atherosclerosis, which occurs when fatty deposits clog and harden arteries,
  • coronary heart disease, caused by the reduced blood supply to the heart muscle,
  • stroke, caused by inadequate blood flow to the brain leading to the death of brain cells,
  • hypertension , occurs when blood pressure is higher than the normal range,
  • cardiac arrhythmias, which are irregular or abnormal heartbeats.

7.2 How can diet and physical activity affect cardiovascular diseases?

There tends to be a delay between the exposure to risk factors such as poor nutrition, insufficient physical activity and tobacco use and the onset of cardiovascular diseases. This risk is increased by biological factors such as obesity, high blood pressure, diabetes and low cardio-respiratory fitness.

Cardiovascular disease death rates therefore tend to reflect risks encountered at some point in the past.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.4.3 Diet, physical activity and cardiovascular disease 

7.3 What nutrients are known to affect cardiovascular diseases?

cheese
Dairy products such as
cheese contain Saturated
fatty acids
© Micro Application

Table 10 Summary of strength of evidence on lifestyle factors

A high intake of dietary fats strongly influences the risk of developing cardiovascular disease (CVD).

Saturated fatty acids commonly found in dairy products and meat raise cholesterol levels. Moreover, studies have also shown trans fatty acids, found in industrially hardened oils, increase the risk of coronary heart disease. While they have been eliminated from spreads in many parts of the world, trans fatty acids are still found in deep-fried fast foods and baked goods.

The most effective replacement for saturated fatty acids in the diet are polyunsaturated fatty acids (PUFAs) which can lower the risk of developing cardiovascular disease. In particular, they are found in soybean and sunflower oils as well as in fatty fish and plant foods. Polyunsaturated fatty acids have many positive effects, notably on blood pressure, heart function, blood clotting, and inflammatory mechanisms.

Most of this evidence is a result of fish consumption studies. In one particular study, a group of patients who survived a heart attack were given fish oils over several years. Compared to patients who did not receive fish oil, this group had a 20% reduction in total mortality, a 30% reduction in cardiovascular death and a 45% decrease in sudden death.

Cholesterol, which is an essential component of cell membranes and certain hormones, is produced by the liver, but it is also present in dairy products, meat and eggs. A high amount of a certain type of cholesterol (Low Density Lipoprotein or LDL) in the blood can lead to its deposition in the arteries that can restrict blood flow and may cause heart problems. It is not clear whether dietary cholesterol is associated with cardiovascular disease, but it is recommended to avoid excessive intake. Cholesterol is not, in fact, required in the diet because it is produced by the liver in sufficient amounts.

Dietary fibre is also a major factor in reducing total cholesterol in the blood and LDL cholesterol in particular. Eating a diet high in fibre and wholegrain cereals can reduce the risk of coronary heat disease.

An intake of 0.8 mg of folic acid could possibly reduce the risk of coronary heart disease (reduced blood supply to the heart muscle) by 16% and the risk of stroke by 24%. Flavonoids, compounds that occur in a variety of foods such as tea, onions and apples, could also possibly reduce the risk of coronary heart disease. There is insufficient evidence to support the theory that antioxidants such as Vitamin E, Vitamin C or b-carotene might reduce the risk of cardiovascular diseases (CVD).

A high intake of salt (sodium) has been linked to high blood pressure, a major risk factor for stroke and coronary heart disease.

There is convincing evidence that a reduction in the daily intake of sodium (by 50 mmol, i.e about 1.2g across the world would lead to reduction in the number of deaths resulting from strokes and coronary heart disease (by about 22% and 16% respectively).

Taking potassium supplements has been shown to reduce blood pressure and the risk of CVD. However, the recommended level of fruit and vegetable consumption supplies an adequate intake of potassium and there is no evidence in favour of long term potassium supplementation to reduce the risk of CVD.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.4.4 Strength of evidence 

7.4 What food items are known to affect cardiovascular diseases?

Consumption of fruits and vegetables has been widely associated with good health. Recent studies show a protective effect against coronary heart disease, stroke and high blood pressure.

Fish consumption also reduces the risk of coronary heart disease. The benefits are most evident in high risk groups. For these groups, consuming 40-60g of fish per day would lead to a 50% reduction in the number of deaths form coronary heart disease. Other dietary factors may also contribute to reducing the risk.

Nuts are high in unsaturated fatty acids and low in saturated fats, which contribute to lowering cholesterol levels. Several animal experiments have suggested that isoflavones, present in soy products, may provide protection against coronary heart disease.

Alcohol can have both a damaging and protective role in the development of cardiovascular disease. Despite convincing evidence that low to moderate alcohol consumption reduces the risk of coronary heart disease, consumption should be limited because of the risk of other cardiovascular diseases and health problems.

Coffee beans contain a substance called cafestol, which can raise the level of cholesterol in the blood and may increase the risk of coronary heart disease. The amount of cafestol in the cup depends on the brewing method: zero for paper-filtered drip coffee and high for unfiltered coffee which is widely drunk in Greece, the Middle East and Turkey.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.4.4 Strength of evidence, Food items and food groups 

7.5 How could cardiovascular diseases be prevented?

To promote cardiovascular heath, intake of saturated fats should be limited to less than 10% of daily energy intake for most people, and to less than 7% for high-risk groups. Products commonly used for cooking, such as hydrogenated fats or coconut and palm oil, contain saturated fatty acids. Limiting the amount of saturated fatty acids consumed can be accomplished by restricting the intake of fat from dairy and meat sources, avoiding the use of hydrogenated oils in cooking, and ensuring a regular intake of fish (once or twice per week). A diet comprising of a total fat intake of up to 35% does not increase the risk of unhealthy weight gain in physically active people who consume a lot of fruits, vegetables, legumes and wholegrain cereals.

Table 10: Summary of strength of evidence on lifestyle factors

A daily intake of 400 to 500 g of fruits and vegetables such as berries, green leafy vegetables and legumes is recommended to reduce the risk of coronary heart disease, stroke and high blood pressure. This daily consumption provides an adequate amount of potassium, which lowers blood pressure and is protective against stroke and cardiac arrythmias. Other beneficial effects are due to the phytonutrients and fibre contained in fruits and vegetables. Indeed, fibre that is also found in wholegrain cereals helps protect against coronary heart disease and lowers blood pressure.

Restricting salt (sodium chloride) intake to less than 5 g per day generally helps to reduce the risk of coronary heart disease and stroke. Restricting salt intake even more, to 1.7g of sodium per day may provide additional benefits such as helping to reduce blood pressure. However, precautions should be taken in special cases such as pregnant women who may be adversely affected by sodium reduction.

Fish consumption once or twice per week is protective against coronary heart disease and stroke. Vegetarians should ensure an adequate intake of the essential fatty acid alpha-linolenic acid which is also found in plant sources (such as canola and soybean oils, pumpkins, and walnuts).

Although low to moderate alcohol consumption may protect against coronary heart disease, other health risks associated with alcohol may outweigh these benefits.

Thirty minutes of moderate physical activity every day may be sufficient to raise fitness of the heart and lungs which in turn may reduce the risk of CVD.A longer duration and a higher activity level would provide an even greater benefit. However, people who are generally inactive should avoid sudden and high-intensity bursts of physical activity.

This text is a summary of: WHO/FAO Diet, Nutrition and the prevention of chronic diseases
Section 5.4.5 Disease-specific recommendations 


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