Nutrition: Essential Fats

Tuesday 08 May 2018

This month I want to look at the subject of essential fats in the diet.

Everyone knows that a high fat diet can lead to obesity and that obesity is associated with increased health risks. What is less commonly known is that depending on the amount and type of fat consumed, dietary fats may also stimulate or inhibit progression of an established cancer.

Which are the essential fatty acids and why they are important?

The group of fats called ‘ESSENTIAL FATS’, are important because we cannot synthesis them ourselves so need to get them from the foods that we eat.

The roles that they play in our health.

  • A good source of energy.
  • They have valuable cell membrane functions.
  • They contribute to the correct structure and fluidity.
  • They are important for efficient hormone and neurotransmitter receptor function.
  • Needed for proper gene expression.
  • They are precursors to short lived local hormones called Eicosanoids.
  • Our brains are 60% fat and the peripheral nervous system is covered by a fatty substance called Myelin which insulates the nerves and protects them from damage.
  • They provide the important vitamins A,D,E and K.

Two of the most important groups of essential fats are the Omega 3 fats and the Omega 6 fats. These are present in foods but in order for the fats to be of benefit to us, they are converted in the body into substances called Prostaglandins. Prostaglandins are hormone like substances. They have many important roles in the body, which we will look at later.

The conversion is quite a complicated business and in order for it to be successful we need an adequate supply of B vitamins and zinc in our diets to help the process. B vitamins of course come from whole grains and yeast products and fermented foods and some in nuts and seeds. Zinc is found in abundantly in oats, nuts, seeds, and beans as well as the animal foods that we may eat.

It is thought that humans evolved on a ratio of 1:1 omega 6 to omega 3. These were the foragers/hunter gatherers. Omega 3 and Omega 6 do compete for absorption so with this in mind it is important not to have a dominance of one or the other in the diet. The hunter gatherers seemed to have got this right!!!.

But the ratio now is thought to be more like 20:1 omega 6 to omega 3. This is mainly due to:

  • The consumption of intensively reared animals fed a high % of vegetable oils In their feed. These oils are high in omega 6.
  • A sharp reduction in the consumption of wild meat and fish which contains Omega 3.
  • The introduction of artificial TRANS fats due to the industrial method of hydrogenating.

Hydrogenated oils are used extensively in the food industry, in processed foods, margarines and low fat spreads. They are rich in omega 6 as well as being changed chemically from a natural to an artificial form by the process of hydrogenation.

It is thought that too much omega 6 to the detriment of omega 3 can be linked with the promotion of cancer. Basically high levels of omega 6 have been shown to promote inflammation. According to Cancer Research UK chronic persistent inflammation is behind a host of health problems including cancer. So what is the link between inflammation and cancer. When the body is inflamed it encourages the immune system to produce inflammatory markers like COX-2 and certain cytokines including Tumour Necrosis Factor (TNF a). The incorrect ratio of omega 6 to omega 3 is at the root. When we have the correct ratio in our diets we benefit in so many ways.

The ideal ratio set by the government should be 3:1 or no more than 5:1 omega 6 to omega 3. When we have this balance we benefit in so many ways.

• A diet with adequate omega 3 has been shown to be anti-inflammatory and helps to prevent the expression of genes that promote cancer.

• Animal studies have shown that omega 3 encourages apoptosis (natural cell death) of cancer cells.

• They have been shown to boost the immune system by increasing T cell levels with a good ratio of T helper cells to T suppressor cells.

So where do we get these essential fatty acids from in our diet? 

All food sources of fats do contain a mixture of essential fats i.e. some omega 3 and some omega 6, but the foods below are dominant in one or the other.

Omega 6.

All natural, cold pressed seed and nut oils including coconut oil, sesame seed oil, sunflower seed oil. Fresh unsalted nuts and seeds. Interestingly, a handful of cashew nuts would give you adequate levels of omega 6 for a day

Omega 3

Oily types of fish like salmon, sardines, tuna, trout, pilchards and mackerel (by far the best most bioavailable sources), pumpkin seeds and pumpkin seed oil and butter, walnuts, flax seeds flaxseed oil, chia seeds. Wild game meats.

It is worth noting that if you buy any oil in a plastic bottle and the oil is golden you can assume that this oil has been very heavily processed. Oils that are natural and cold pressed usually come in glass bottles and are a similar colour to the seed or nut that they were made from.

What we should be avoiding (if possible)

Processed foods, Hydrogenated/Trans fats (read labels), low fat foods, too much fat from animal products.

The whole subject of essential fats is a very complex one but I have tried to pick out the bones so to speak, to help you understand and make good choices. By taking some simple steps then you will naturally be having a good ratio of 3 to 6 without worrying.


Blog originally written by Caroline August 2016 - checked March 2021

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