omega-3 omega-6 | essential fats
Nature or nurture? There is an age-old debate about whether performance is primarily ‘in your genes’ or develops in response to training. The common consensus is somewhere in between: that we inherit a set of genes which determine our potential, but it’s our training and nutrition that allow us to reach that potential. However, new evidence suggests this fatalistic approach to our genetic make-up is misplaced; fascinating research is emerging from the world of nutrition to suggest that essential fats in our diet can exert significant control over key metabolic genes in our cells, particularly those involved with fat storage, fat burning and glycogen synthesis. In plain English this means that, while you might not be born with the ideal genetic make-up for your chosen sport or event, correct fatty acid nutrition could help to ‘reprogramme’ your genetic code!
There are two principal essential fats: alpha-linolenic acid (sometimes called omega-3) and linoleic acid (omega-6). These two fats are essential because their chemical structure means that they can be used to make hormone-like substances called prostaglandins, which go on to regulate a host of other functions in the body. However, these fats cannot be synthesised by the body, which is why we rely on getting them ‘ready-made’ from the diet.
The complex structure of the fats also makes them very chemically reactive; put simply, they readily undergo chemical change and ‘fall apart’ when exposed to heat, light or air. This means that storing, cooking or processing foods rich in essential fatty acids (EFAs) inevitably leads to a loss in nutritional value. The problem is that we need more of these EFAs per day than any other single nutrient – measured in tablespoons, not milligrams! And the task of obtaining enough of them in unadulterated form in today’s world of tinned, dried, frozen, fast and processed food is a major challenge.
[...]
The role of EFAs in human nutrition has long been recognised; dietary omega-3 and omega-6 fats are needed for the synthesis of prostaglandins, which help regulate certain aspects of metabolism, such as blood viscosity, inflammatory processes, blood cholesterol and fat levels, and water balance. Additionally, it is now widely accepted that a low ratio of EFAs to saturated fatty acids is associated with an increased risk of coronary heart disease (CHD).
New findings on EFAs and obesity
However, more recent research on EFA nutrition has yielded some intriguing new findings. One of these is that increased intakes of these essential fats appear to reduce tissue levels of triglycerides (stored fats), which improves the sensitivity of insulin (the hormone that drives amino acids and glucose into muscle cells), so reducing the risk of obesity and CHD(1). Initially, these beneficial effects of EFAs were thought to be due to changes in the fatty acid composition of the cell membranes, leading to subsequent alterations in hormonal signalling. However, when researchers dug a little deeper it became apparent that something else was going on.
They discovered that these fats, particularly those of the omega-3 family, play essential roles in the maintenance of energy balance and glucose metabolism. In particular, they observed a phenomenon known as ‘fuel partitioning’, whereby dietary EFAs were able to direct glucose (from digested carbohydrates) towards glycogen storage while at the same time directing other fatty acids in the body away from triglyceride synthesis (ie fat storage) and towards fatty acid oxidation! In addition, these studies suggested that omega-3 fatty acids have the unique ability to enhance thermogenesis (the burning of excess fat to produce heat), thereby reducing the efficiency of body fat deposition(2-7). In simple terms, this fuel partitioning phenomenon appears to conserve carbohydrate while simultaneously shedding fat – exactly what most athletes would give their right arm for!
Further study of this fuel partitioning effect led to the discovery that the EFAs were somehow boosting the production of enzymes involved with fatty acid oxidation (such as carnitine palmitoyltransferase, which helps transport fatty acids into the mitochondria of the cells for burning) while at the same time down-regulating the production of enzymes involved in fat synthesis, such as fatty acid synthase (8-12).
At first it was assumed that this ‘up-regulation’ of fat burning/glycogen synthesising enzymes and ‘down-regulation’ of fat storage enzymes occurred through hormonal signalling; in other words that the EFAs were somehow altering the cell membranes, causing a change in chemistry and leading to altered enzyme production by the genes responsible. However, these changes in gene transcription occur too quickly to be explained in this way; there seemed to be a much more direct effect. And eventually researchers discovered, to their amazement, that these EFAs were able to control gene expression directly via a steroid-like substance called PPARα.
PPARα is known as a ‘lipid-activated transcription factor’. This means it switches on key genes by binding to DNA, but only when it has been activated itself by binding to lipids such as EFAs. And it turns out that the genes it switches on are precisely those which code for enzymes involved in fat burning! Not only was this a remarkable discovery in itself, it was also the first time science had clearly demonstrated that nutritional components of the diet can exert direct control over the function of genes.
Nature or nurture? There is an age-old debate about whether performance is primarily ‘in your genes’ or develops in response to training. The common consensus is somewhere in between: that we inherit a set of genes which determine our potential, but it’s our training and nutrition that allow us to reach that potential. However, new evidence suggests this fatalistic approach to our genetic make-up is misplaced; fascinating research is emerging from the world of nutrition to suggest that essential fats in our diet can exert significant control over key metabolic genes in our cells, particularly those involved with fat storage, fat burning and glycogen synthesis. In plain English this means that, while you might not be born with the ideal genetic make-up for your chosen sport or event, correct fatty acid nutrition could help to ‘reprogramme’ your genetic code!
There are two principal essential fats: alpha-linolenic acid (sometimes called omega-3) and linoleic acid (omega-6). These two fats are essential because their chemical structure means that they can be used to make hormone-like substances called prostaglandins, which go on to regulate a host of other functions in the body. However, these fats cannot be synthesised by the body, which is why we rely on getting them ‘ready-made’ from the diet.
The complex structure of the fats also makes them very chemically reactive; put simply, they readily undergo chemical change and ‘fall apart’ when exposed to heat, light or air. This means that storing, cooking or processing foods rich in essential fatty acids (EFAs) inevitably leads to a loss in nutritional value. The problem is that we need more of these EFAs per day than any other single nutrient – measured in tablespoons, not milligrams! And the task of obtaining enough of them in unadulterated form in today’s world of tinned, dried, frozen, fast and processed food is a major challenge.
[...]
The role of EFAs in human nutrition has long been recognised; dietary omega-3 and omega-6 fats are needed for the synthesis of prostaglandins, which help regulate certain aspects of metabolism, such as blood viscosity, inflammatory processes, blood cholesterol and fat levels, and water balance. Additionally, it is now widely accepted that a low ratio of EFAs to saturated fatty acids is associated with an increased risk of coronary heart disease (CHD).
New findings on EFAs and obesity
However, more recent research on EFA nutrition has yielded some intriguing new findings. One of these is that increased intakes of these essential fats appear to reduce tissue levels of triglycerides (stored fats), which improves the sensitivity of insulin (the hormone that drives amino acids and glucose into muscle cells), so reducing the risk of obesity and CHD(1). Initially, these beneficial effects of EFAs were thought to be due to changes in the fatty acid composition of the cell membranes, leading to subsequent alterations in hormonal signalling. However, when researchers dug a little deeper it became apparent that something else was going on.
They discovered that these fats, particularly those of the omega-3 family, play essential roles in the maintenance of energy balance and glucose metabolism. In particular, they observed a phenomenon known as ‘fuel partitioning’, whereby dietary EFAs were able to direct glucose (from digested carbohydrates) towards glycogen storage while at the same time directing other fatty acids in the body away from triglyceride synthesis (ie fat storage) and towards fatty acid oxidation! In addition, these studies suggested that omega-3 fatty acids have the unique ability to enhance thermogenesis (the burning of excess fat to produce heat), thereby reducing the efficiency of body fat deposition(2-7). In simple terms, this fuel partitioning phenomenon appears to conserve carbohydrate while simultaneously shedding fat – exactly what most athletes would give their right arm for!
Further study of this fuel partitioning effect led to the discovery that the EFAs were somehow boosting the production of enzymes involved with fatty acid oxidation (such as carnitine palmitoyltransferase, which helps transport fatty acids into the mitochondria of the cells for burning) while at the same time down-regulating the production of enzymes involved in fat synthesis, such as fatty acid synthase (8-12).
At first it was assumed that this ‘up-regulation’ of fat burning/glycogen synthesising enzymes and ‘down-regulation’ of fat storage enzymes occurred through hormonal signalling; in other words that the EFAs were somehow altering the cell membranes, causing a change in chemistry and leading to altered enzyme production by the genes responsible. However, these changes in gene transcription occur too quickly to be explained in this way; there seemed to be a much more direct effect. And eventually researchers discovered, to their amazement, that these EFAs were able to control gene expression directly via a steroid-like substance called PPARα.
PPARα is known as a ‘lipid-activated transcription factor’. This means it switches on key genes by binding to DNA, but only when it has been activated itself by binding to lipids such as EFAs. And it turns out that the genes it switches on are precisely those which code for enzymes involved in fat burning! Not only was this a remarkable discovery in itself, it was also the first time science had clearly demonstrated that nutritional components of the diet can exert direct control over the function of genes.
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