This is the third installment in a discussion of dietary fats, with respect to prostate cancer. See also:
"Foods/Supplements-Vitamins: Fats - [1] Oleic & Stearic Acids – (Olive Oil & Animal Fat)"
"Foods/Supplements-Vitamins: Fats - [2] Palmitic acid"
A. Summary.
Myristic acid is a saturated fat generally found at low levels in some foods. For many, dairy will be the main source. Men with PCa might already be aware that dairy products are associated with progression & will have cut down on intake. It's not clear to me whether the negative PCa study findings for myristic acid are other than a reflection of dairy risk.
However, in the absence of dairy products, myristic acid blood levels can still be elevated in men who have introduced coconut oil into their diets. Coconut oil is 17% myristic acid. Understandably, there are no coconut oil PCa studies. The prudent thing would be to avoid coconut oil.
B. Introduction.
Myristic acid is a saturated fat with a backbone of 14 carbons. Most will be unaware of it, but it is associated with PCa risk.
{"Myristic acid is named after the nutmeg Myristica fragrans." "Nutmeg butter has 75% trimyristin, the triglyceride of myristic acid." [B1]}
B1. Myristic acid sources.
- coconut oil: 17%
- butter: 7%
- beef tallow: 4%
- cheddar cheese: 3%
C. Studies.
[Ca] (2003 - Finland)
"Associations between serum fatty acid composition as well as fatty acid intakes and prostate cancer risk were examined in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study. The cohort included 29,133 male smokers aged 50–69 years. During 5–8 years of follow-up, 246 prostate cancer cases were diagnosed."
"Twofold risk was found in the highest quartile of serum myristic acid compared with the lowest quartile ..."
"Ruminant fat, derived mainly from dairy products, is the major source for myristic acid in Finland, but dietary intake data did not show association for these products."
Dairy itself is associated with PCa risk. Various reasons have been put forward, including (a) calcium - high intakes suppress hormonal vitamin D, & (b) IGF-I - a human growth factor associated with PCa. With multiple suspects, I wonder if the study finding can be trusted.
The ATBC study involves smokers & those with a history of smoking. Study results may not be identical for non-smokers.
[Cb] (2008 - Japan) - a low-risk population not associated with dairy products.
"The relative risks ... comparing the highest with the lowest quartiles of total dairy products, milk, and yogurt were 1.63 .., 1.53 .., and 1.52 .., respectively."
"Relative risks ... on comparison of the highest with the lowest quartiles of myristic ... acid {was} 1.62"
"... myristic acid may well reflect the intake of dairy products."
[Cc] (2008 - Europe - EPIC study)
"This was a nested case-control analysis of 962 men with a diagnosis of prostate cancer after a median follow-up time of 4.2 y and 1061 matched controls who were taking part in the European Prospective Investigation into Cancer and Nutrition."
"There {was a} significant positive association between myristic ... acid and risk of high-grade prostate cancer."
"Men from Sweden had the highest proportion of ... myristic ... acid, and {this} fatty acid {was} lowest among the Greek men."
[Cd] (2012 - Sweden)
"Dietary intake of 14 fatty acids was analyzed in a population-based cohort of 525 Swedish men with prostate cancer in Örebro County (1989-1994)."
"Among men with localized prostate cancer, hazard ratio of ... 2.39 ... for saturated myristic acid ... intakes demonstrated increased risk for disease-specific mortality for the highest quartile compared with the lowest quartile."
"Epidemiologic studies previously reported positive associations between saturated myristic acid and risk of prostate cancer, although none explored disease-specific mortality. Our findings of increased prostate cancer-specific mortality for high versus low myristic acid intake among men diagnosed with localized disease agree, in general, with those from other studies of myristic acid and prostate cancer risk. Myristic acid makes up approximately 11% of fatty acids found in dairy products and may raise cholesterol levels."
-Patrick
[B1] en.wikipedia.org/wiki/Myris...
[Ca] cebp.aacrjournals.org/conte...
[Cb] cebp.aacrjournals.org/conte...