Written by Greg Arnold, DC, CSCS. The researchers determined that there is a significantly reduced risk of hip fractures in those individuals that had the highest blood levels of omega-3.
Menopause is a normal change in a woman’s life when she stops menstruating, specifically for 12 months in a row. This cessation is marked by changes in the levels of 2 hormones, estrogen and progesterone, that usually occur between the ages of 45 and 55 years of age and may cause hot flashes, night sweats or sleeping problems and lead to perceptions of fatigue, stress, tension, and a thinning of bones. According to U.S. Census data from 2000, there are about 37.5 million women reaching or currently at menopause (1).
It is the thinning of bones during menopause that is a significant health concern as postmenopausal osteoporosis contributes to an estimated 1.45 million fractures, including 222,000 hip fractures, each year in U.S. women. Hip fracture incidence is projected to increase by 51% and increase healthcare costs by 49% in the United States by 2025 (2,3). Now a new study (4) suggests that monitoring blood levels of omega-3 fatty acids may better predict risk of fracture in postmenopausal women.
In this case-control study, researchers analyzed blood samples of 324 postmenopausal women participating in the Women’s Health Initiative (5) who suffered a hip fracture and matched them by age, race, and hormone use with 324 women in the Women’s Health Initiative who did not suffer a hip fracture. They found that those in the highest one-third (tertile) of total omega-3 acid blood levels (6.86-16.44% of total fatty acids) had a 45% reduced risk of hip fracture versus those with the lowest tertile of total omega-3 fatty acid blood levels (3.51-5.84% of total fatty acids) (p = 0.0492).
When they looked at specific types of omega-3 fats, they found a protective effect with the plant form of omega-3, alpha linolenic acid (ALA) and a marine form of omega-3, EPA (Eicoapentaenoic Acid). For alpha linolenic acid, those in the highest tertile (0.28–0.93%) had a 56% reduced risk of hip fracture compared to those in the lowest tertile (0.08–0.21%) (p = 0.0154). For eicosapentanoic acid, the researchers found a 54% reduced risk in the highest tertile (0.54-3.85%) compared to those with the lowest tertile (0.04-0.37%) (p = 0.0181). No protective effects were found with the other marine form of omega-3, DHA (Docosahexaenoic acid) (p = 0.1675).
The researchers also found a significant increased risk of hip fracture for those with a high omega-6/omega-3 fat ratio in the blood. Specifically, those in the highest tertile (6.08-10.59) had a 96% increased risk of hip fracture compared to those in the lowest tertile (1.48-5.00) (p = 0.0399).
Unfortunately, because the researchers did not examine the diet of the subjects, no actual intakes of omega-3 fats were assessed so no recommendations were made on what omega-3 intakes may elicit a protective effect against hip fractures. They went on to conclude that, “These results suggest that higher [red blood cell percentages of] a-linolenic acid, as well as eicosapentaenoic acid and total omega-3 fats may predict lower hip fracture risk. Contrastingly, a higher red blood cell omega-6/omega-3 ratio may predict higher hip fracture risk in postmenopausal women.”
Source: Orchard, Tonya S., et al. “The association of red blood cell n‐3 and n‐6 fatty acids with bone mineral density and hip fracture risk in the women’s health initiative.” Journal of Bone and Mineral Research 28.3 (2013): 505-515.
© 2013 The American Society for Bone and Mineral Research
Posted July 24, 2013.
References:
- “Women’s Reproductive Health: Menopause” posted on the CDC website
- Braithwaite RS, Col NF, Wong JB. Estimating hip fracture morbidity,mortality and costs. J Am Geriatr Soc. 2003;51(3):364–70.
- Burge R, Dawson-Hughes B, Solomon DH, Wong JB, King A, Tosteson A. Incidence and economic burden of osteoporosis-related fractures in the United States. 2005–2025. J Bone Miner Res. 2007;22(3): 465–75.
- Orchard TS. The association of red blood cell n-3 and n-6 fatty acids with bone mineral density and hip fracture risk in the women’s health initiative. J Bone Mineral Res 2013 Mar;28(3):505-15. doi: 10.1002/jbmr.1772.
- Design of the Women’s Health Initiative clinical trial and observational study. The Women’s Health Initiative Study Group. Control Clin Trials. 1998;19(1):61–109. Cited. in: PubMed; PMID. 9492970.
