Postmenopausal women who consume a diet rich in omega-3 fatty acids may have a lower chance of hip fractures, according to a recent study published in the Journal of Bone and Mineral Research.
Omega-3 and omega-6 polyunsaturated fatty acids (PUFA) in red blood cells (RBCs) are an objective indicator of PUFA status and may be related to hip fracture risk. Researchers from Ohio State University conducted the study to examine RBC PUFAs as predictors of hip fracture risk in postmenopausal women.
The researchers used blood samples and hip fracture records from the Women’s Health Initiative (WHI), a large national prospective study of postmenopausal women that enrolled participants between 1993 and 1998 and followed them for 15 years. For the new study, the sample consisted of red blood cell samples and records from 324 pairs of WHI participants, half of whom had broken their hips before Aug. 15, 2008, and the other half composed of age-matched controls who had never broken a hip.
The study showed higher levels of omega-3 fatty acids from both plant and fish sources in those blood cells were associated with a lower likelihood of having fractured a hip. In addition to omega-3s, the researchers looked at omega-6 fatty acids, which are generally plentiful in a Western diet. The study also showed that as the ratio of omega-6 fatty acids to omega-3s increased, so did the risk for hip fracture. The current American diet contains between 15 and 17 times more omega-6 than omega-3. Lionelic acid composes 99% of Americans' omega-6 intake is found in corn, soybean, safflower and sunflower oils.
“Inflammation is associated with an increased risk of bone loss and fractures, and omega-3 fatty acids are believed to reduce inflammation. So we asked if we would see fractures decrease in response to omega-3 intake," said Rebecca Jackson, the study’s senior author and a professor of endocrinology, diabetes and metabolism at Ohio State University. “One thing that was critically important was that we didn’t use self-report of food intake, because there can be errors with that. We looked directly at the exposure of the bone cell to the fatty acids, which is at the red blood cell level. Red blood cell levels also give an indication of long-term exposure to these fatty acids, which we took into account in looking for a preventive effect."
The specific omega-3 sources associated with lower risk for broken hips were alpha-linolenic acid (ALA), which comes from plant sources such as flaxseed oil and some nuts, and eicosapentaenoic acid (EPA), which is found in fatty types of fish. The other marine-sourced omega-3, docosahexaenoic acid (DHA), on its own did not have a significant link to lower hip-fracture risk, “but all three omega-3s were in the protective direction," said Tonya Orchard assistant professor of human nutrition at Ohio State and first author of the study.
“Though it’s premature to make a nutrition recommendation based on this work, I do think this study adds a little more strength to current recommendations to include more omega-3s in the diet in the form of fish, and suggests that plant sources of omega-3 may be just as important for preventing hip fractures in women," Orchard said.
The analysis from the WHI showed that higher levels of omega-3 and two other specific kinds of omega-3s alone were associated with a lower risk of hip breaks in the study sample of 324 pairs of participants who had hip fractures.
Although further analyses of the data from WHI is required, a recent study found that women who consume omega-3 fatty acids found naturally in fish like salmon are less likely to develop breast cancer.
