Friday, 16 August 2013

How does fat consumption affect humans? 1

This is the current advice from Western governments.  Eat vegetable oils and avoid animal fats.

Butter has been turned into the devil incarnate along with lard, beef dripping and fatty meats. Human beings ate fatty diets including animal fats for centuries.  Industrially produced vegetable oils are a recent innovation.

Lipidologist, Chris Masterjohn, gives an overview of traditional diets and the role of animal fats in aiding absorption of essential micronutrients.

(Please note that other videos in this series are provided as links, because Youtube didn't enable me to post them in a frame.  I highly recommend taking the time to watch the whole series):

Chris looks at the balance of macronutrients in 3 traditional Pacific Island diets.  Some ate less than a third of the diet as fat while others consumed more than half the calories as fat.  He analyses the types of fat (saturated, mono and poly unsaturated MUFA & PUFA) and the ratios.  They all ate more saturated fat and much lower percentages of PUFAs than modern Western diets.

We are told that science proves that animal fats cause heart disease, as illustrated by the famous Time Magazine cover and article.   Sadly scientists ran poorly designed research, changed the groups during the work, merged the data, failed to randomise the trials properly, didn't streamline the trials to focus on a single intervention, ignored clear data from the research and drew fallacious conclusions.  Researchers continue to muddle correlation with cause (eg people carry umbrellas when it rains, versus umbrellas trigger rain).

Chris uses 2 criteria to include analysis of research:  randomised controlled trial and a single factor intervention.  This excludes the Oslo diet heart study; STARS; Lyon diet heart study; DART 1; Finnish mental hospital study.

Masterjohn takes us through 6 trials that fit his 2 criteria:

Rose & colleagues 1965 vegetable oil substitution trial (corn oil isn't helpful and seems to be harmful);

Sydney diet-heart study (the data indicates that PUFAs can kill you - the scientists concluded that men who have had heart attacks make poor research subjects);

Saint Vincent's Hospital Study (at 10 years they changed the control group, making it impossible to infer cause-effect from the study);

The Medical Research Council Study looked at soya oil, but introduced a confounder in getting subject to take half the oil unheated, thus removing some effects of heat damage.  No effects found);

The Minnesota Coronary Survey (double blind study, large, included women, but very short.  Over time the PUFA diet subjects had poorer survival rates)

The LA Veterans Administration Hospital Study (double blind study, long trial, mean age over 60.  After 2 years, vegetable oils increased the risk of other diseases including cancer, after 6-7 years survival rates from non heart diseases on PUFAs decrease markedly).

Chris draws the following conclusions from the LA VA Administration Hospital Study:

-  The effects of animal fat, cigarette smoking and Vitamin E deficiency on heart disease mortality cannot be distinguished from one another.

-  Long term vegetable oil consumption may increase mortality from cancer and other causes.

-  Animal fat may protect against the adverse effects of cigarette smoking and vitamin E deficiency

-  Studies with a duration of fewer than seven years are not long enough to determine the  true effects of vegetable oils

The study authors conclude that clinical trials must be planned for periods well in excess of 8 years, rather than the 5 year periods that have been the usual goal.

There is no evidence that substituting vegetable oils for animal fats reduces heart disease or saves lives and may in fact do the opposite.  Vegetable oils appear to promote cancer.

NHS Choices says in 'Fat the Facts':

Fats to cut down on

As part of a healthy diet, we should try to cut down on food that is high in saturated fat.

Eating a diet high in saturated fat can cause the level of cholesterol in your blood to build up over time. Raised cholesterol increases your risk of heart disease.

What a pity that the research doesn't support this contention.  I choose to believe the science.

Masterjohn cites several unanswered questions:

What is the long term effect of vegetable oils?

What are the effects in healthy, free living youth from the beginning of life?

Does it make a difference whether the vegetable oils are balanced in Omega 3 or not?

How do they interact with other nutrients in the diet?

What is the effect of high quality, nutrient dense animal fats like good butter instead of the poor quality, vitamin E deficient fats used in the last study?

We are guinea pigs for these oils which have never given evidence for preventing heart disease.  They may in fact be toxic.

Chris concludes:

-  Clinical trials have miserably failed to demonstrate harmful effects of saturated fat.

-  Vegetable oils may promote hart disease and likely promote cancer.

-  Animal fats can help maximise nutritional status, provent physical degeneration and promote vibrant health.

Chis Masterjohn doesn't promote any particular type of diet or macronutrient ratio. 

He advocates a common sense view. 

He recognises that a range of different diets have promoted health and that people's needs vary throughout life, depending on what micronutrients the body needs for health.

He does not advocate eating a high saturated fat diet or the opposite, but aims to dispel myths and fear about fat.

Eat as much of these traditional, healthy whole foods as you need (including organ meat) and enjoy it!

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