“Is a diet rich in saturated fat  a health risk or not?” (Johnson, 2016, p.18).

A dog whistle question to get researchers/scientists, food commentators and self-styled experts hot under the collar.

New evidence would suggest it is a health risk (Wang et al., 2016). Actually, the new evidence is a new statistical analysis of historical and ongoing studies: the Nurses Health Study (started in 1980) and the Health Professionals Follow-up Study (started in 1986).

Same Researchers, Same General Results, Different Papers

For those eagle-eyed readers, you will notice that several of the 2016 study authors are continually using the same study data (although updated) to write broadly similar papers over a period of years! They merely rotate who is the lead author, examples include.

• In 1993, Willet and colleagues suggest that “These findings support the hypothesis that consumption of partially hydrogenated vegetable oils may contribute to occurrence of CHD.”
• In 1997, Hu and colleagues stated “We previously reported [see above] on the relation of dietary intake of trans unsaturated fat to the incidence of coronary disease among women in the Nurses’ Health Study over an eight-year period. The present analyses extend those findings to a total of 14 years of follow-up to examine the effect of total dietary fat and specific major types of fat and to estimate the effects of substituting carbohydrates or unsaturated fat for saturated fat and trans unsaturated fat.
• In 2005, Oh and colleagues suggests that “Findings continue to support an inverse relation between polyunsaturated fat intake and CHD risk, particularly among younger or overweight women. In addition, trans-fat intake was associated with increased risk of CHD, particularly for younger women.”
• In 2007, Field and colleagues suggested that “Overall, there was a weak positive association between total fat intake (beta=0.11) and weight gain.”

Dissent in the Ranks

Unlike Wang and colleagues (2016) who appear to continually utilise the Nurses Health Study as the basis of their papers, Chowdhury and colleagues (2014) decided to utilise a variety of data sources for their study (a meta-analysis), and yes they did include the Nurses Health Study.

Chowdhury and colleagues utilised a variety of prospective, observational studies and randomised controlled trials.

Their overarching conclusion suggested “Current evidence does not clearly support cardiovascular guidelines that encourage high consumption of polyunsaturated fatty acids and low consumption of total saturated fats.”

Willet and Stampfer (2014) took offence “Dr. Willett emphasized that because this meta-analysis contains multiple serious errors and omissions, the study conclusions are misleading and should be disregarded.”

“Although the media have made much of the “disappointing” results from the Women’s Health Initiative (WHI) Dietary Modification Trial, it would be a serious mistake to use these new findings as reason to load up on sausage, butter, and deep-fried fast food.” “The Women’s Health Initiative Dietary Modification Trial was started back in 1993, at a time when dietary fat was seen as a dietary evil and the low-fat diet was thought to be a straightforward route to preventing heart disease, some cancers, and the epidemic of obesity that was beginning to sweep the country.” (Harvard School of Public Health, n.d.).

“But Dr. Frank Hu [interestingly one of Wang’s co-author’s], a professor of nutrition and epidemiology at the Harvard School of Public Health, said the findings should not be taken as “a green light” to eat more steak, butter and other foods rich in saturated fat.” (O’Connor, 2014).

“The single macronutrient approach is outdated,” said Dr. Hu, who was not involved in the study.” (O’Connor, 2014). Not involved in the study (LOL, understatement), that’s because he is diametrically opposed to their standpoint.

One respected researcher, T Colin Campbell stated “According to journalist Anahad O’Connor,[1] the researchers[2] claimed that saturated fat, “the type found in meat, butter and cheese”, does not cause heart disease, suggesting that it is not as bad as we have been led to believe.” (Campbell, 2014).

Of course what O’Connor actually wrote was “But a large and exhaustive new analysis by a team of international scientists found no evidence that eating saturated fat increased heart attacks and other cardiac events. (O’Connor, 2014).

Did not increase NOT did not cause, two very different things; poor Dr Campbell, very poor. I have to confess that I do like the rest of his article.

Why Haven’t You Answered the Question?

I love fruit and vegetables (very healthy for you apparently), I also love cakes and pastries loaded with saturated fats (not so healthy for you apparently).

My primary health concern is not my diet, it is the effects of secondary (passive) smoking. My parents and grandparents all ‘smoked like chimneys’ in the house. Both my grandparents, on my mother’s side, smoked and died from cancer in their 80s. Both my parents smoked for decades. Although I plan on living to 100+, I don’t actually have much choice in the matter.

At the age of 42, I can:

• Run 1.5 miles (2.4 km) in 10 minutes;
• Complete 100+ press-ups in 2 minutes;
• Complete 100+ sit-ups in 2 minutes; and
• Complete 50 burpees in 2 minutes.

My resting heart is 55 bpm;  my blood pressure is 118/73; I drink in moderation; and generally eat a balanced diet.

Although you can’t apply statistics to the individual, you will generally find that individuals exhibit two or more risk factors (e.g. they sit on their arse for prolonged periods, drive rather than walk, generally eat a poor diet and generally have low levels of exercise/physical activity (walking upstairs to bed isn’t exercise!)).

What’s The Answer?

 

You may have noticed that I didn’t actually answer the question, merely pointed out some negativeness and inconsistencies expressed by others.

As reported in the New Scientist in March 2015, nine out of ten people hold, to varying extents, a delusional belief (Lawton, 2015). Based on this, regardless of what commentators state (on either side of the argument), people will decide for themselves what to belief about dietary fats and their effects.

 

References

Johnson, I. (2016) Steak Out. New Scientist. 16 July 2016, p.18.

Wang, D.D., Li, Y., Chiuve, S.E., Stampfer, M.J., Manson, J.E., Rimm, E.B., Willett, W.C. & Hu, F.B. (2016) Association of Specific Dietary Fats With Total and Cause-Specific Mortality. JAMA Internal Medicine. 176(8), pp.1134-1145. doi:10.1001/jamainternmed.2016.2417.

Field, A.E., Willett, W.C., Lissner, L. & Colditz, G.A. (2007) Dietary Fat and Weight Gain among Women in the Nurses’ Health Study. Obesity (Silver Spring). 15(4), pp.967-976. DOI: 10.1038/oby.2007.616.

Oh, K., Hu, F.B., Manson, J.E., Stampfer, M.J. & Willett, J.C. (2005) Dietary Fat Intake and Risk of Coronary Heart Disease in Women: 20 Years of Follow-up of the Nurses’ Health Study. American Journal of Epidemiology. 161(7), pp.672-679. DOI: 10.1093/aje/kwi085.

Hu, F.B., Stampfer, M.J., Manson, J.E., Rimm, E., Colditz, G.A., Rosner, B.A., Hennekens, C.H. & Willet, W.C. (1997) Dietary Fat Intake and the Risk of Coronary Heart Disease in Women. New England Journal of Medicine. 337, pp.1491-1499. DOI: 10.1056/NEJM199711203372102.

Willet, W.C., Stampfer, M.J., Manson, J.E., Colditz, G.A., Speizer, F.E., Rosher, B.A., Sampson, L.A. & Hennekens, C.H. (1993) Intake of Trans Fatty Acids and Risk of Coronary Heart Disease among Women. Lancet. 341, pp.581-585.

Chowdhury, R., Warnakula, S., Kunutsor, S., Crowe, F., Ward, H.A., Johnson, L., Franco, O.H., Butterworth, A.S., Forouhi, N.G., Thompson, S.G., Khaw, K-T., Mozaffarian, D., Danesh, J.& Di Angelantonio, E. (2014) Association of Dietary, Circulating, and Supplement Fatty Acids With Coronary Risk: A Systematic Review and Meta-analysis. Annals of Internal Medicine. 10(6), pp.398-406. doi:10.7326/M13-1788 .

Willett, W., Sacks, F. & Stampfer, M. (2014) Dietary Fat and Heart Disease Study is Seriously Misleading. Available from World Wide Web: https://www.hsph.harvard.edu/nutritionsource/2014/03/19/dietary-fat-and-heart-disease-study-is-seriously-misleading/. [Accessed: 07 August, 2016].

Harvard School of Public Health (n.d.) Low-Fat Diet Not a Cure-All. Available from World Wide Web: https://www.hsph.harvard.edu/nutritionsource/low-fat/. [Accessed: 07 August, 2016].

O’Connor, A. (2014) Study Questions Fat and Heart Disease Link. Available from World Wide Web: http://well.blogs.nytimes.com/2014/03/17/study-questions-fat-and-heart-disease-link/. [Accessed: 07 August, 2016].

Campbell, T.C. (2014) A Fallacious, Faulty and Foolish Discussion About Saturated Fat. Available from World Wide Web: http://nutritionstudies.org/fallacious-faulty-foolish-discussion-about-saturated-fat/. [Accessed: 07 August, 2016].

Lawton, G. (2015) Are You Deluded? The Strange Things We Believe. Available from World Wide Web: https://www.newscientist.com/article/dn27267-are-you-deluded-the-strange-things-we-believe/. [Accessed: 05 August, 2016].