During aging and in elderly populations it is very common for bone loss to place individuals at risk for one or more fractures. Mild loss of bone is refereed to as osteopenia, whereas severe loss of bone is known as osteoporosis. Bone fracture risk is higher for those with osteoporosis and a great deal of research is being conducted to diagnose, prevent, and treat fractures in the elderly. Nutrition can pay a role in age-related bone loss and a common recommendation is to make sure you are getting plenty of calcium since calcium is the major mineral building block of bone. This recommendation has resulted in many individuals taking calcium supplements. However supplements are often taken with no consideration to the quality and composition of regular foods being consumed. Perhaps these can have a protective effect if chosen wisely.
In a recent article by Byberg and others (2014) in the Journal of Bone and Mineral Research, fruit and vegetable intake was analyzed in men and women to determine if there were statistical associations between intake levels and incidence of hip fracture. The rationale was that daily intake of at least 5 servings of fruits and vegetables is associated with reduced risk of disease (e.g., diabetes, cardiovascular disease). Further, prior studies have indicated fruit and vegetable intake was associated with increased bone mineral density. Some studies also exist linking fruits and vegetables to reduced forearm fractures, but the specific foods and doses could not be linked to the reduction in fracture risk. Therefore, in the Byberg et. Al 2014 study, the authors sought to clarify the relationship between fruit and vegetable intake and hip fracture risk.
The Takehome: The study indicated that, in both men and women, low intakes of fruit and vegetables (less than 1 serving) were associated with increases of hip fracture compared to 3-5 servings. Over 5 servings of fruits and vegetables did not appear associated with any increased reduction in hip fracture. So, there appears to be a limit to the power fruits and vegetables; you can’t reduce your fracture risk to zero by increasing your intake beyond 5 servings a day. As with all questionnaire-based studies, this study is limited by the ability of the participants to accurately recall the details of their past eating habits. The study also doesn’t address the mechanism by which fruits and vegetables might protect against hip fractures, though the authors speculate it may be tied to the roles these foods might play in reducing oxidative stress and inflammation, and increasing intestinal calcium absorption. Nevertheless, the findings are of note given the study’s large sample size and detailed data set. How many servings of fruits and vegetables are you eating each day?
- Swedish men (40,644) and women (34,947) free of cancer and cardiovascular disease (age 45-83 years old) were studied.
- Fruit and vegetable consumption was recorded based on surveys given to participants asking them how often, on average, they had consumed each food during the previous year.
- Responses were converted to average daily intakes based on age and sex-specific portion sizes.
- There were 14 vegetable entries tracked (carrot, beetroot, broccoli, cabbage, cauliflower, lettuce, onion, garlic, peas, pea soup, pepper, spinach, tomato, and “other” vegetables) and 5 fruit entries tracked (apple, banana, berry, orange/citrus, and “other” fruits)
- The outcome measure was a participant’s first incidence of a hip fracture.
- Information on prevalent diseases, body composition, size, medication, smoking and various other variables were incorporated in the statistical design as covariates.
- Depending on the specific analysis used, 5 or between 3 and 5 servings of fruits and vegetables per day was used as the reference point.
- Cox’s proportional hazards regression models were used for assessing the association between fruits and vegetables and hip fracture.
- The was an inverse association between fruit and vegetable intake and hip fracture such that less than or equal to 1 serving a day was associated with an almost 50% increased rate of fracture, as compared to 3-5 servings per day.
- Compared with 5 servings a day, lower intakes of fruits and vegetables were associated with higher rates of hip fracture.
- Intakes above 5 servings per day did not appear associated with any increased benefit to hip fracture incidence.
- There was no interaction between fruit and vegetable intake and possible co-variants like potassium, magnesium, calcium, or body mass index (BMI). So, at the very least, these factors were not underlying the observed fruit & vegetable association.
- Fruit and vegetable consumption was self-reported by the participants (not monitored by the investigators).
- Only certain covariates (education, physical activity, smoking) were considered and other factors not considered may be contributing to the observed relationship between fruit and vegetable intake and reduced hip fracture incidence.
- This study does not point to causation, only association between fruit & vegetable intake and reduced hip fracture incidence.