Chowdhury et al, More forests & more trees and more "Eureka!" moments with cheese.

Like Siri-Tarino et al, Forests & Trees and "Eureka!" moments, Chowdhury et al is a meta-analysis of many studies. See Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. I don't have access to the full study, but Google Image Search found Figure 2.

From http://annals.org/data/Journals/AIM/929862/6ff2_Figure_2_RRs_for_coronary_outcomes_in_prospective_cohort_studies_of_circulating_fatty_acid.jpeg

All saturated fatty acids have a RR for CHD of 1.06 (95% CI 0.86 - 1.30).
∴ There's no association between saturated fat intake and the RR for CHD.

Before VLC'ers do a dance of joy, consider the Forest plot for individual saturated fatty acids.
Palmitic acid has a RR for CHD of 1.15 (95% CI 0.96 - 1.37).
Stearic acid has a RR for CHD of 1.23 (95% CI 0.93 - 1.61).

Red meat & saturated fats synthesised by DNL aren't looking too good. However...
Pentadecanoic acid has a RR for CHD of 0.94 (95% CI 0.67 - 1.32).
Margaric acid has a RR for CHD of 0.77 (95% CI 0.63 - 0.93).
Pentadecanoic acid and Margaric acid combined have a RR for CHD of 0.81 (95% CI 0.62 - 1.06).

What are Pentadecanoic acid & Margaric acid found in? The clue's in the title:-
Say cheese: saturated fat in dairy may protect against diabetes.

The article in the Telegraph is actually referring to Differences in the prospective association between individual plasma phospholipid saturated fatty acids and incident type 2 diabetes: the EPIC-InterAct case-cohort study.

Of the omega-3 fatty acids...
Eicosapentaenoic acid has a RR for CHD of 0.78 (95% CI 0.65 - 0.94).
Docosahexaenoic acid has a RR for CHD of 0.79 (95% CI 0.67 - 0.93).
Eicosapentaenoic acid and Docosahexaenoic acid combined have a RR for CHD of 0.75 (95% CI 0.62 - 0.89).

Of the omega-6 fatty acids...
Arachidonic acid has a RR for CHD of 0.83 (95% CI 0.74 - 0.92).

Of the trans-fatty acids...
Trans-oleic acid has a RR for CHD of 1.20 (95% CI 0.39 - 3.73).
Trans-linoleic acid has a RR for CHD of 1.36 (95% CI 0.83 - 2.22).

Historical perspectives on the impact of n-3 and n-6 nutrients on health, by Bill Lands.

Here's Fig. 1. from http://www.sciencedirect.com/science/article/pii/S0163782714000253

Relating tissue HUFA balance with blood cholesterol and heart attacks. Results from the 25-year follow-up in the Seven Countries Study [35] were discussed in an earlier review [10] which noted that “Food energy imbalances which elevate blood cholesterol may be fatal only to the degree that omega-6 (n-6) exceeds omega-3 (n-3) in tissue HUFA. Such evidence raises questions about the hypothesis that blood cholesterol levels cause CHD.” Northern Europe and Southern Europe have abbreviations “No.” and “So.”, respectively. The Figure is reprinted with permission of the publisher.

Hat-tip to Dr. Thomas Dayspring for Tweeting this review.

Fig. 1 is interesting, as it shows a significant association between 25-year CHD mortality and Serum Total Cholesterol for every region except Japan. What's different about Japan, compared to Northern Europe, USA, Serbia, Southern Europe & Crete?

According to Measuring Blood Fatty Acids as a Surrogate Indicator for Coronary Heart Disease Risk in Population Studies , Philippines & Iceland have lower % linoleic acid than Japan. Where's the CHD vs TC data?

Could another difference be that the Japanese eat rice, a relatively intact grain, instead of foods made from wheat grain dust (i.e. flour) as their main source of dietary carbohydrates?

See also Using 3–6 differences in essential fatty acids rather than 3/6 ratios gives useful food balance scores , and Omega 3-6 Balance Score.

Some thoughts on the essentiality of dietary carbohydrates.

I didn't know that there's a watch strap called Essentiality. I do, now.

From https://svpply.com/item/3229602/Swatch_Skin_Collection_Silver_Essentiality

This is a book-marking post for thoughts I had in https://www.facebook.com/TheFatEmperor/posts/1442430506020812.

"The human body does not need carbohydrates from an external food source, because it is capable of very precisely and correctly assembling its own amounts of glucose that is needed in very small amounts for auxiliary and specialized functions." - Igor Butorski.

1) It's not very precise. See http://nigeepoo.blogspot.co.uk/2012/04/how-eating-sugar-starch-can-lower-your.html

2) It's not enough to fuel high-intensity exercise. See http://nigeepoo.blogspot.co.uk/2011/02/funny-turns-what-they-arent-and-what.html

3) Using the above argument, the human body does not need saturated fats & monounsaturated fats from an external food source, because it is capable of very precisely and correctly assembling its own amounts of saturated fats & monounsaturated fats (out of carbohydrate) that are needed in very small amounts for auxiliary and specialized functions.

If we only consumed Essential Fatty Acids, Essential Amino Acids, Vitamins, Minerals, Fibre/Fiber, Water & Anutrients, there wouldn't be much to eat. Also, there wouldn't be a source of chemical energy to generate heat energy & mechanical energy. That's what dietary carbohydrates & fats are for.

Respiratory Exchange Ratio/Respiratory Quotient (RER/RQ) varies with carbohydrate & fat intake, as the body preferentially oxidises the fuel that's most readily available.

RER/RQ varies with Exercise Intensity.
Low-intensity exercise results in mostly fats being oxidised.
High-intensity exercise results in mostly carbohydrates being oxidised.
Medium-intensity exercise results in a mixture of fats & carbohydrates being oxidised.

Ancel B. Keys' critique of "Diet and coronary thrombosis. Hypothesis and fact, by John Yudkin. The Lancet, 1957."

Ancel B. Keys has come in for a lot of flak recently over alleged "cherry-picking" of data for his 6/7 Countries studies. Here's Keys' critique:- "SUCROSE IN THE DIET AND CORONARY HEART DISEASE" of Dr. John Yudkin's "15 Countries" article.

Keys accuses Yudkin of bias, cherry-picking countries that fit his own hypothesis.

Here are some plots from Keys' 11 Countries article.

5-Year CHD cases/1,000 men vs Sucrose %E.

5-Year CHD cases/1,000 men vs Sat Fats %E.

Sucrose %E vs Sat Fats %E.

So there you have it.

Saturated fats Saturated fats Saturated fats.

George Henderson left the following comment. I think that the information in it deserves a bigger audience.

Saturated fats seem to get the blame for everything nowadays. "Saturated fats clogged my arteries". "Saturated fats gave me cancer". "Saturated fats stole my job". O.K, I've done that joke before.

There are saturated fats, there are saturated fats, there are saturated fats, there are saturated fats, there are saturated fats and there are saturated fats. Saturated fats are an ester of Glycerol (a 3-carbon alcohol) and three saturated fatty acids (SFA's). There are roughly six categories of SFA's.

1) Short chain SFA's such as Acetic acid, Propionic acid, Butyric acid (found in butter and also what soluble fibre ferments into in the colon) and Caproic acid.
2) Medium chain SFA's such as Caprylic acid, Capric acid, Lauric acid and Myristic acid.
3) Long chain SFA's such as Stearic acid.
4) SFA's behaving like Palmitic acid.
5) Odd chain SFA's such as Pentadecylic acid and Margaric acid.
6) Very long chain SFA's such as Behenic acid.

See http://en.wikipedia.org/wiki/List_of_saturated_fatty_acids

In foods, the above SFA's are associated with different things.
1) and 2) don't get associated with much polyunsaturated fatty acids (PUFA's), e.g. dairy and tropical nuts.
3) and 4) are more likely to be associated with long-chain PUFA's, e.g. meats, poultry, temperate nuts.
5) is associated with CLA and not much PUFA's, e.g. dairy from grass-fed animals.

See also Siri-Tarino et al, Forests & Trees and "Eureka!" moments and Chowdhury et al, More forests & more trees and more "Eureka!" moments with cheese.

Siri-Tarino et al, Forests & Trees and "Eureka!" moments.

Here's Fig. 2 from Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease:-

Risk ratios and 95% CIs for fully adjusted random-effects models examining associations between saturated fat intake in relation to coronary heart disease and stroke.

The above "Forest" plot has a subtotal RR of 1.07 (95% CI 0.96 1.19). The overall conclusion is that there's no association between saturated fat intake and the RR for CHD. Hmmm.

I looked at the data in Table 3. Of the 16 studies contributing to the CHD results, only 3 of them specify high sat fat intakes over a wide range. The results from these 3 studies are as follows:-

Pietinen et al: RR=0.93 (95% CI 0.6, 1.44).
Mann et al: RR=2.77 (95% CI 1.25, 6.13).
Boniface et al: Pooled RR = 1.37 (95% CI 1.17, 1.65).

The results from Pietinen et al are statistically-insignificant (95% CI values are way above & below 1) with an overall slight protective effect. The results from Mann et al have a RR >> 1 with both 95% CI's >1 and the results from Boniface et al have a RR >1 with both 95% CI's >1.

Other studies either have sat fat intakes varying from very low to low, or specify mean/median sat fat intakes without values for highest & lowest tertiles/quartiles/quintiles etc. Other studies have results that are statistically-insignificant.

However, there are some studies that show a slight protective effect of small amounts of sat fats. How come?

Thanks to George Henderson, I had a "Eureka!" moment. He posted a link to Dietary intake of saturated fat by food source and incident cardiovascular disease: the Multi-Ethnic Study of Atherosclerosis.

Here's Fig. 1 from that study.

HRs and 95% CI's of CVD risk according to quintiles of energy-adjusted SF from different sources (n = 5209).

The Meat SF plot has a net positive slope (bad news, but the range of intake is very small), the Butter & Plant SF plots are random, but the Dairy SF plot has a net negative slope (good news). Dairy saturated fats in amounts of up to 10g/day are protective against CHD. As the Dairy sat fat intake is too small to have a significant effect on lipids, what's the mechanism? I think that it's Vitamin K2. See Chowdhury et al, More forests & more trees and more "Eureka!" moments with cheese.

When you average out the results from all studies, the result is null. This is data dilution statistics.

EDIT: See also Study: Saturated Fat as Bad as Sugar!

Completing the trine: Which are the safest fats?

First, watch this video by Chris Masterjohn.

Diets very high in pufas (polyunsaturates) are not beneficial to heart health or longevity. Flora? No thanks!

Here's a chart. The beige & grey bars represent pufas (omega-6 & omega-3).

Comparison of dietary fats

The yellow bars represent monounsaturates and the orangey-red bars represent saturates. I consider these to be harmless, as long as you don't go mad and eat them in such large amounts that you gain weight.

Bearing in mind the information in the video, plus the information in Fats: Spawn of Satan or Dogs' Doodads? , I use only fats from the bottom 6 for cooking (olive oil and butter, actually).

Flaxseed oil can be used as an omega-3 supplement for vegetarian/vegan women, as omega-3 pufas are as rare as rocking-horse poo in most foods (apart from oily fish).

Non-vegetarian/vegan people can get their long-chain omega-3 pufas (EPA & DHA) from oily fish. As vegetarian/vegan men barely produce any DHA from the omega-3 in flaxseed oil, they should get it from algal DHA supplements. See Extremely Limited Synthesis of Long Chain Polyunsaturates in Adults: Implications for their Dietary Essentiality and use as Supplements.