Myristic acid is a saturated fat found primarily in coconut oil, palm kernel oil and butter fat. Few recent studies have focused on possible associations between myristic acid and breast cancer risk. The results of animal studies have been inconsistent. However, past epidemiological studies have found a link between myristic acid or coconut oil intake and heightened breast cancer risk.
Now a new prospective study presented at the American Association for Cancer Research Annual Meeting has reported that high circulating levels of myristic acid may increase breast cancer risk.

Previous studies have reported a link

A 2009 Greek study that compared the fatty tissue of breast cancer patients and healthy women in Crete reported that high myristic acid was associated with sharply increased breast cancer risk. A 2006 Philippine study reported that women who frequently used boiling in coconut milk as a food preparation method had more than double the risk of breast cancer as those who did not.

Food sources of myristic acid

As noted above, myristic acid is a found primarily in coconut oil, palm kernel oil and full-fat dairy foods. Coconut products contain more myristic acid than dairy foods, as the table below shows.
CoconutServingMyristic acid
Coconut oil4 oz.19.0 g
Coconut milk1 cup10.0 g
Coconut meat1 cup5.8 g
 
DairyServingMyristic acid
Butter4 oz.9.4 g
Milk1 cup1.7 g
Cheese, fontina1 cup3.9 g
Ice cream1 cup2.4 g
Palm kernel oil (which is not the same as palm oil and is produced in far smaller quantities) has a saturated fat profile similar to coconut oil. Palm kernel oil is generally used in home and personal care products and in some processed foods. For example, several companies use it in producing high-end sports or nutrition bars coated with chocolate or yogurt in order to keep the coatings from melting during transport. Palm kernel oil should be listed on the nutrition label of any packaged food that incorporates it.

Latest research links myristic acid to breast cancer

The study referenced above was designed to investigate the association between various types of dietary fat intake and risk of breast cancer. To conduct the study, the authors obtained data concerning 905 postmenopausal women with breast cancer and 1,813 matched healthy controls from the Cancer Prevention Study II (CPS-II) Nutrition Cohort, part of a major U.S. prospective mortality study. The data was used to calculate the association between breast cancer risk and blood plasma levels of 60 phospholipid fatty acids. The analysis was adjusted for established breast cancer risk factors (alcohol, smoking, and HRT use, BMI and waist circumference, and change in weight between age 18 and enrollment).
Blood samples were collected upon enrollment during 1997 and 1998. Blood plasma levels of adrenic, dihomo-γ-linolenic, heptadecanoic, monounsaturated fatty, myristic, palmitoleic, palmitic, trans α-linolenic and vaccenic acids all were found to have an association (either positive or negative) with breast cancer risk. However, only the myristic acid association retained statistical significance after adjustment.
Myristic acid was found to be positively associated with risk of breast cancer; similar associations observed for both ER+ (estrogen receptor positive) and ER- breast cancer. The authors conclude that higher circulating levels of myristic acid may increase breast cancer risk. More research is need to confirm this result and establish the mechanism of action by which myristic acid increases risk, according to the authors.
Please see the myristic acid tag and our coconut food page for more information.