Coronary heart disease, or cardiovascular disease, is one of the most common causes of death, causing 29.2% of global deaths according to a World Health Report in 2003. Despite public health campaigns to reduce cholesterol and increase activity levels, most people still haven’t made the lifestyle changes required to reduce the risk of heart disease. Yet there are several simple dietary changes that can significantly improve the health of your heart, postponing or even reducing the onset of heart disease.
What is heart disease?
Heart disease is usually a combination of high blood pressure, atherosclerosis (‘furring up’ of the arteries) and high cholesterol levels, although other factors are involved. Although we commonly use the term ‘heart disease’, these conditions also affect the blood vessels going to and from the heart because substances such as fats are carried in the bloodstream.
Hypertension
Hypertension is continued high blood pressure. A ‘normal’ blood pressure reading is 120/80, where the first figure is systolic blood pressure (when the heart is contracting) and the second figure is diastolic blood pressure (when the heart is filling with blood). This figure tends to increase from our mid-twenties as we age. The higher the blood pressure, the greater the likelihood of damage to the inside of the artery walls. Once damaged, fatty substances are more likely to stick to the inside of these blood vessels and ‘fur up’ the arteries, causing atherosclerosis.
Atherosclerosis
Atherosclerosis is the result of the ‘furring up’ on the inside of the artery walls. As this plaque formation builds up, it reduces the space for blood to travel through, which increases blood pressure, creating even more damage to the artery walls. ()nce the smooth inner membrane of an artery is damaged, fatty substances are more likely to stick to its rough surface, worsening the atherosclerosis and narrowing the artery even more. Although high blood pressure and atherosclerosis are two separate conditions, they each cause the other.
Arteriosclerosis
This is a hardening of the artery walls often found alongside atherosclerosis. Our artery walls are made of the foods that we eat, the types of fats we consume and the balance of minerals like calcium, magnesium, sodium and potassium. This all affects how flexible our artery walls are. Eating too many ‘bad’ fats (also known as hydrogenated, saturated, refined or trans fats) creates rigid artery walls, whereas ‘good’ fats (also known as polyunsaturated fats) from fish, nuts and seeds promote flexibility. A diet high in salt (sodium) or calcium, or not enough magnesium, also contributes to rigid artery walls which Inil lo ‘give’ when blood pressure increases, making them more likely to be damaged. Smoking also contributes to arteriosclerosis.
Cholesterol
Not all cholesterol is bad for us; only oxidised low density lipoprotein (LDL) cholesterol (‘bad’ cholesterol) increases the risk of heart disease. Our diet only provides approximately 20% of our cholesterol. We make the rest ourselves, using it to form cell membranes, to make hormones and to form bile for fat digestion. High levels of high density lipoprotein (HDL) cholesterol (‘good’ cholesterol) helps to counteract high levels of ‘bad’ cholesterol.
Reducing cholesterol in your diet has little effect on your cholesterol levels, so what can you do if you have high cholesterol?
‘Bad’ fats seem to increase production of cholesterol in the liver, so cut down on fatty meats, full-fat dairy produce, cakes, biscuits and ice cream.
Reduce any excess body fat around your middle (central obesity), as this increases the amount of ‘bad’ cholesterol in the liver.
Oxidation
Oxidation occurs naturally throughout the body, but without enough antioxidants such as vitamin C or E to keep it in check, oxidation can become a problem. Oxidation occurs when an unstable atom or molecule, also known as a free radical, attaches to molecules or cells and destabilises the molecule or cell next to it. This can result in a chain reaction of molecular damage causing cell damage, mutations or cell death. Heated and processed fats (trans and hydrogenated fats) are the most likely to become oxidised.
When LDL cholesterol or refined fats become oxidised, they are more likely to damage artery walls, and in trying to repair this damage, a build up of blood cells and fibres create plaque. This then contributes to atherosclerosis; the deposits inside the arteries made from different types of blood cells, calcium and the ‘bad’ cholesterol begin to block the inside of the artery where blood flows through, contributing to heart disease. So, it seems that several factors contribute to heart disease:
- Increased blood pressure.
- Too much ‘bad’ fat in the diet.
- Oxidation of fats.
- Stored body fat around the middle.
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