We are continually berated with the message that saturated fat(SFA) is bad for us and that we should alter our habitual diet in order to keep consumption to a minimum.
According to the official NHS website:
“Eating a lot of saturated fat can increase the cholesterol in your blood. High levels of cholesterol can increase your risk of:
Cholesterol is a type of fat that your liver makes from the fatty food that you eat.”
It goes on to say that:
“Your body needs small amounts of fat to help it work normally. However, some types of fat are healthier than others. There are two main types of fat in food:
- saturated fat, and
- unsaturated fat.
It’s a good idea to eat less saturated fat, to reduce the health risks linked with high cholesterol levels.”
People are advised to lower consumption of the main sources of saturated fat which include foods such as:
- butter, lard and ghee (oil made from butter),
- fatty meats and meat products, such as sausages and pies,
- full fat milk,
- cream, soured cream, crème fraîche and ice cream,
- cheese, particularly hard cheese,
- some savoury snacks, such as crisps,
- coconut oil, coconut cream and palm oil,
- biscuits, cakes and pastries, and
- sweets and chocolate.
More specific advice is to:
- Choose lean meat or skinless poultry, instead of fatty meat or meat products.
- Trim the fat off meat before you cook it.
- Grill meat instead of frying it.
- Eat less pastry, cakes, biscuits and crisps.
- Choose lower-fat dairy foods, like 1% fat milk, low-fat yoghurt, or low-fat crème fraîche.
- Cook with small amounts of unsaturated vegetable oil, such as sunflower, olive or rapeseed oil.
On the other hand we are encouraged to use:
- Reduced-fat spread instead of butter
- 1% fat milk or skimmed milk instead of whole or semi-skimmed milk
- Lower-fat yoghurt.
In Blog 15 I explained how the benefits of the polyunsaturated vegetable oils have been exaggerated and that there are genuine concerns that the typical diet in northern Europe and in the USA contains excessive amounts.
As the extract from the NHS website shows the rationale for reducing SFA and increasing polyunsaturated fats is entirely dependent on the “fact” that blood cholesterol is a risk factor for heart disease. The evidence cited in Blog 8 demonstrates unequivocally that this is absolute rubbish!
Further confirmation that the villification of SFA is totally unjustified is provided by a recent meta-analysis based on an evaluation of prospective epidemiological studies on the relation between CVD and the intakes of SFA.
When the data from all the selected studies were combined there was no association of SFA intake with disease prevalence after adjustment for other nutrients whenever possible.
Based on this meta-analysis, there was
“no significant evidence to conclude that dietary saturated fat(SFA) is associated with an increased risk of CHD, stroke or CVD”(1).
A more critical examination of the science provides a convincing case that that SFA actually makes a very valuable contribution to the nourishment of the body. It is crucial to recognise that the term “saturated fat” consists of a range of chemical entities which usually contain an even number of carbon atoms the smallest being butyric acid with 4 and behenic acid with 22. Here is a brief selection of some of the functions/benefits of SFA(2):
- Cell membranes require SFA to be “waterproof” in order to function properly
- The heart prefers the long chain fatty acids palmitic acid(16 Cs) and stearic acid (18 Cs) to carbohydrates to carbohydrates as a source of energy
- Bones need SFA in order to assimilate calcium effectively.
- The short and medium chain length fatty acids, which have up to 12 carbon atoms do not need to be emulsified by bile salts and so are rapidly absorbed into the blood stream from the small intestine. They are especially valuable because they boost the immune system and possess anti-microbial, anti-viral and anti-tumour properties. Lauric acid (C12) is particularly effective
- It is now known that the LDL cholesterol exists in particles which vary in size. At one end of the extreme they are densely packed and it is now believed that these particular ones initiate the damage which ultimately results in coronary heart disease. At the other end are the large fluffy particles which are relatively benign. SFA in the diet favours the formation of the large particles.
There is now a very large volume of sound research which leads to the inevitable conclusion that those who are attempting to comply with the official advice to reduce saturated fat are not improving their health and are almost certainly damaging it. Not only are they missing out on valuable nutrients they are also increasing omega-6 polyunsaturated fats which pushes up omega-6:omega-3 ratio thereby increasing the requirement for omega-3s(Blog 15) but they are also increasing intake of carbohydrates which contributes to the development of obesity and a range of chronic diseases.
Sources of SFA such as butter and various meats also contain a selection other key nutrients such as vitamins which will be lost to diet by those who take steps to limit their intake of SFA. I will explain further in a future blog.
- P. Siri-Tarino (2010) American Journal of Clinical Nutrition 91 (3) pp. 535-546
- Mary Enig(2000) “The Skinny on Fats” http://www.westonaprice.org/know-your-fats/skinny-on-fats?