Cholesterol levels and heart health
Since all animal cells manufacture cholesterol, all animal-based foods contain cholesterol in varying amounts. Dietary sources of cholesterol include cheese, egg yolks, beef, pork, poultry, fish, and prawns. However dietary cholesterol intake does not correlate well with blood plasma cholesterol levels. There is a correlation between saturated fat intake and cholesterol levels but most of the circulating plasma level of cholesterol is made by our own liver.
Cholesterol is essential for our bodies. It is in every cell membrane, is needed to make hormones, bile acids for digestion and for synthesising vitamin D. It is transported by lipoproteins we know as HDL and LDL . Most of the cholesterol in our bodies is produced in the liver with dietary cholesterol adding to this. The amount absorbed by the body depends on how much is available from the diet. The biosynthesis of cholesterol is directly regulated by the cholesterol levels present. A
higher intake from food leads to a decrease in production, whereas a lower intake from food has the opposite eﬀect. Most
evidence shows that low HDL cholesterol is a risk factor for cardiovascular events. Some people are genetically predisposed
to high cholesterol levels.
Low density lipoprotein (LDL) carries cholesterol to the cells that need it, but if there’s too much cholesterol for the cells to
use it, it can build up in artery walls contributing to disease of the arteries; for this reason, LDL is known as “bad cholesterol”. Recent evidence is pointing to links between Alzheimer’s and cholesterol. Lack of certain nutrients can aggravate this process.
High Density Lipoprotein (HDL) particles transport cholesterol back to the liver, either for excretion or for other tissues that synthesise hormones. Large numbers of HDL particles correlates with better health outcomes. HDL can remove cholesterol from the macrophages of the arterial wall. Thus increased concentrations of HDL correlate with lower rates of atheroma and HDL is sometimes referred to as “good cholesterol”. Better levels of HDL are associated with lower levels of inflammatory markers.
The Lipid Hypothesis- new insights.
The work of Ancel Keys, an American physiologist, led to ‘the lipid hypothesis’ which links raised blood cholesterol levels to the occurrence of heart disease. An accumulation of evidence resulted in the acceptance of the lipid hypothesis by most of the medical community; however, a growing minority argues that the evidence does not support it, and that mechanisms independent of blood cholesterol levels are responsible. This debate is referred to as the “cholesterol controversy”. It is closely related to the saturated fat and cardiovascular disease controversy. More evidence is pointing towards the danger of excess sugar and carbohydrate consumption as many high fat consuming communities do not have cardiovascular problems. Importantly they do not consume sugar or refined carbs. Norway and Innuit peoples are amongst them. Many more studies are ongoing.
5mmol/L or less for healthy adults
4mmol/L or less for those at high risk
As a general guide, LDL levels should be:
3mmol/L or less for healthy adults
2mmol/L or less for those at high risk
An ideal level of HDL is above 1mmol/L. A lower level of HDL can increase your risk of heart disease.
Your ratio of total cholesterol to HDL may also be calculated. This is your total cholesterol level divided by your HDL level. Generally, this ratio should be below 4, as a higher ratio increases your risk of heart disease.
To summarise recent studies , Protective foods
Raw nuts and seeds
Plant polyphenols and plant based foods
Anti inflammatory foods
Damaging foods /diets
Oils -Excess Omega 6 : Omega 3 ratio. Vegetable oils Trans fats- these are processed hydrogenated margarines etc
High carb and sugar foods
Typical western diet