Fat and Cholesterol in Human Milk

Fat and Cholesterol in Human Milk

by Mary G. Enig, PhD

Fat and cholesterol are very important components in human milk. In fact, the milk from a healthy mother has about 50 to 60 percent of its energy (kilocalories) as fat.1 The cholesterol in human milk supplies an infant with close to six times the amount most adults consume from their food.1

When a woman has many children, the level of fat in her milk usually decreases with each succeeding child. This will not happen, however, if the mother maintains a high quality diet. In some parts of the world, such as China, the new mother is given a diet very high in animal fat that includes 6-10 eggs a day and almost 10 ounces of chicken and pork for at least a month after the birth of her infant. This diet ensures that the level of fat in her milk is as high as possible.2

Some women produce milk that has a fat level similar to the Guernsey or Jersey cow (high fat) and some produce milk that more closely resembles the Holstein cow (lower fat). The higher fat is more desirable, of course, for the developing infant. The higher fat milk will have more of the fat molecules that are needed for their many functional properties, and will also supply enough energy so that all of the protein can be used by the infant for development. Fat is spoken of as "protein sparing." Without adequate fat, the protein in human milk cannot be used.

Studies of milk from 224 Danish mothers showed that they produced milk with a very wide range of fat content.1 The average amount of fat was 39 grams per liter of milk and the range was from 18 grams to 89 grams per liter of milk. That is the equivalent of an average milk fat content of 3.9 percent with the range between 1.8 percent and 8.9 percent. This would mean that some babies would be getting the equivalent of 2 percent milk and some would be getting the equivalent of table cream, with the average infant getting the equivalent of whole Guernsey or Jersey milk. Studies have shown that the average levels of fat in the milk of Canadian women to be 3.2 percent, and the fat levels in two different areas in China to be either the same at 3.2 percent or somewhat higher at 3.8 percent.2

Healthy women consuming good quality natural foods with a good balance of animal and vegetable foods have the potential to produce higher fat content, but there are several diet and disease states that can interfere with milk fat production. Lactating women who are on high-carbohydrate, lowfat diets may see a decrease in their milk fat levels. Women who are malnourished may also have a decrease in milk fat. Women who have infections or metabolic disorders also have lower milk fat levels.3

Although the level of total fat in human milk varies nearly fivefold, the amounts of the different major fatty acid categories are somewhat less variable and the values show overlap. For example, typical milk from French mothers has an average of 44 percent saturated fatty acids, with a range from 39-47 percent. Studies of milk from Dutch mothers showed averages of 38-52 percent saturated fatty acids. Typical milk from Sudanese mothers has an average of 46 percent saturated fatty acids with a range of 36-55 percent. From Spanish mothers the average reported is 41 percent saturated fatty acids and the range is 32-51 percent.1

The elongated omega-3 fatty acids found in fish oils are also found in the milk of healthy, properly fed mothers, and especially mothers who consume fish and/or fish oils. Some mothers can make these elongated omega-3 fatty acids from the shorter omega-3 fatty acids. When there is none of the shorter omega-3 (alpha-linolenic acid 18:3) in the mother's diet, as has been recorded in some Nigerian mothers, the amounts of lauric acid and capric acid are very high, making up close to a third of the total fatty acids. This appears to be nature's way of helping to protect the infant from infections and also helping to conserve the important elongated omega-3 fatty acids. There have been animal studies showing that there were adequate elongated omega-3 fatty acids in the tissues even when no omega-3 was present in the diet as long as the fat that was in the diet was coconut oil. Coconut oil is rich in lauric acid.

The average amount of antimicrobial fatty acids, particularly lauric acid and capric acid, found in the milk of lactating mothers around the world is not usually as high as that reported in Nigeria, but amounts as low as 2 percent and as high as 20 percent have been reported. French mothers average 6 percent with ranges of 2-12 percent. Japanese mothers are reported to produce up to 9 percent lauric and capric acids. Studies in the US showed that diabetic mothers have very low levels, around 2 percent, but mothers with cystic fibrosis have about 8 percent. Adding coconut oil to the diet of lactating mothers raised the levels of lauric and capric acid to about 20 percent.

About the Author
Mary G. Enig, PhD is a nutritionist in private practice in Silver Spring, MD. She can be contacted at marye@enig.com or by fax at (301)680-8100.

REFERENCES

1. Jensen RG. Lipids in Human Milk. Lipids 1999;34:1243-1271.
2. Chen ZY, Kwan KY, Tong KK, Ratnayake WMN, Li HQ, Leung SSF. Breast Milk Fatty Acid Composition: A Comparative Study Between Hong Kong and Chongqing Chinese. Lipids 1997;32:1061-1067.


Source: http://www.westonaprice.org/children/humanmilk.html