Monday, January 24, 2011

The Lipid Hypothesis And The Fat Of The Matter

The Lipid Hypothesis is.....

"A widely accepted postulate that hyperlipidemia–eg, cholesterol, and to a lesser degree, other lipids in the circulation is responsible for CAD, the major cause of death in the US, levels which, when altered by dietary or pharmacologic manipulation, ↓ risk of ASHD-related morbidity."

So in laymen's terms it means that high fat consumption = high cholesterol = heart disease. So for the last 30 years we have been told to eat low fat/high carb and limit cholesterol causing foods, namely animal products and certain others like coconut.

The argument now is whether it was sound advice?From the Gary Taubes New York Times article "What if it's all been a big Fat Lie";

"These researchers point out that there are plenty of reasons to suggest that the low-fat-is-good-health hypothesis has now effectively failed the test of time. In particular, that we are in the midst of an obesity epidemic that started around the early 1980's, and that this was coincident with the rise of the low-fat dogma. (Type 2 diabetes, the most common form of the disease, also rose significantly through this period.)...the percentage of fat in the American diet has been decreasing for two decades. Our cholesterol levels have been declining, and we have been smoking less, and yet the incidence of heart disease has not declined as would be expected. "

Dr.Eades makes reference to Time Magazine's article in 1984 as the virtual beginning of the low fat era and the mistakes and oversights.....

"Its piece on cholesterol in the March 26, 1984 issue was a devastating hit piece on both dietary cholesterol and dietary fat.  Reading this article today, it’s amazing how it drips with misinformation.  At the time, however, most people – physicians included – accepted it as gospel......"

The European Food Information Council(EUFIC) presents what seems to be a balanced summary of the contentious issue of dietary fat/cholesterol and has resisted the polarization between the low fat and high fat camps. Not only do they explain what fatty acids are(triglycerides) but they break them down into the four categories;saturated, monounsaturated, polyunsaturated(Omega 6/Omega 3) and trans fatty acids. They also explain what cholesterol is, why it is important and the role it and dietary fat have in health and wellbeing.

 A few tibits to whet your appetite....pardon the pun.

The importance of dietary fat.

"•Fat is the main energy store in the body and the most concentrated source of energy in the diet - 1g of fat provides 37kJ (9 kcal), more than double that provided by either protein or carbohydrate (4 kcal). The body's fat deposits are used to meet energy demands when dietary energy is limited, for example where people have a poor appetite or during starvation. They may also be needed when energy requirements are high such as during high levels of physical activity and for growing babies and children.

•As well as being an energy reserve, fat deposits cushion and protect vital organs and help insulate the body.

•In the diet, fat is a carrier for the fat-soluble vitamins A, D, E and K, and enables their absorption. It provides the essential fatty acids, linoleic acid (omega-6) and alpha-linolenic acid (omega-3)."

What is cholesterol?Why is it important?

"Cholesterol is a fat-like substance which occurs naturally in all animal tissues including the human body. A certain amount of cholesterol is used by the body for building up cell membranes, for sex hormones and bile acids, which aid in the absorption and digestion of dietary fats."

Polyunsaturated fats in diet.

To much of a good thing yet too little of a good thing? It is generally accepted that the perfect ratio of polyunsaturated fats between Omega 6 and Omega 3 is 2/1. The Standard American Diet(SAD) usually has ratios ranging from 10-1 to 20 -1.

"Polyunsaturated fatty acids from the omega-6 family have potent LDL-cholesterol-lowering properties, which helps to protect against heart disease. However very LARGE AMMOUNTS of omega-6 polyunsaturated fats can cause a REDUCTION in the 'good' HDL cholesterol levels. Because of this and because of concern regarding potentially ADVERSE effect of polyunsaturated fatty acids on LDL oxidation, excessive amounts of polyunsaturated fatty acids should be AVOIDED."

Trans fats - Evil!

"Trans fatty acids not only raise LDL-cholesterol in the same way as saturated fatty acids, but they also LOWER the level of the good HDL-cholesterol. "

 Note - research seems to indicate that while saturated fat does raise LDL(bad) cholesterol it also raises HDL levels at the same time so essentially they balance each other out. In other words saturated fats may in fact be(possibly) neutral when it comes to blood cholesterol levels.Testing has also improved so the old standard of LDL/HDL total cholesterol is now considered more as a state of balance or as a ratio.

"When measurements of serum cholesterol (cholesterol levels in the blood) were first done, only the total of both HDL ("good cholesterol") and LDL ("bad cholesterol") were read. Now that testing has become more sophisticated, researchers look more at the balance of these two types of cholesterol. They note whether a substance raises cholesterol levels of HDL or LDL levels. In some cases, certain foods lower total cholesterol, but only by lowering good HDL cholesterol while at the same time actually raising levels of the bad LDL cholesterol. Studies now show that coconut oil often actually increases the good HDL cholesterol, while lowering LDL. So TOTAL cholesterol levels may actually INCREASE, but in a very FAVORABLE ratio.

A good read and easily understood.....

Many of the clinical studies connecting dietary SFA to increased cholesterol are also suspect in their methodology and scope. Here is an excellent summary of several of the often quoted observational studies that just do not (overwhelmingly) support the Diet-Heart Hypothesis.Another excellent read.....

"Overall, the literature does not offer much support for the idea that long term saturated fat intake has a significant effect on the concentration of blood cholesterol. If it's a factor at all, it must be rather weak, which is consistent with what has been observed in multiple non-human species. I think it's likely that the diet-heart hypothesis rests in part on an over-interpretation of short-term controlled feeding studies."

 It seems all so confusing. Eat this not that. This is good and this is bad. Unfortunately most clinical studies reveal data that can be manipulated in different ways (potentially) depending upon the researcher's biases and personal motives.What to do?

 Ultimately I think the key to dietary fats lies in both balance and lifestyle. We need all types of fat(less the trans fats of course) to be healthy. Saturated fatty acids are not the villians while polyunsaturated Omega 6 is definitely not the hero. Monosaturated fats are important and are found in both vegetable and animal sources(don't let the anti -meat folk convince you otherwise). If there is a hero in waiting in the dietary fat world it is the polyunsaturated Omega 3 fatty necessary for good health yet so ignored in Western diets.

Balance your dietary fat through a variety of foods(yes - even us low carbers have variety) and get some exercise. I think both the lowfat high carb/high fat low carb camps can agree that exercise is a vital key to good health and wellbeing regardless of your chosen way of eating.

1 comment:

Blogger said...

3 Studies PROVE Why Coconut Oil Kills Belly Fat.

The meaning of this is that you actually kill fat by consuming coconut fats (including coconut milk, coconut cream and coconut oil).

These 3 studies from large medicinal magazines are sure to turn the traditional nutrition world upside down!