Could routinely skipping breakfast or eating a late dinner actually affect your bones? According to a new study, it’s certainly possible.
The research, published Aug. 28 in the Journal of the Endocrine Society, is the first to suggest a specific link between these eating patterns and a higher risk of osteoporotic bone fractures, according to the authors.
Osteoporosis occurs when bone mineral density decreases, making bones weaker and more prone to fractures. The disease affects 10 million Americans and is four times as likely to affect women, especially after menopause.
While scientists have long established smoking, alcohol use, and lack of exercise as risk factors for osteoporosis, the role of broader dietary patterns has been less clear—prompting the researchers to investigate the effects of daily eating habits.
“The study does strengthen the idea that lifestyle patterns may affect bone health, beyond just individual nutrients,” said Theresa Gentile, MS, RD, CDN, spokesperson for the Academy of Nutrition and Dietetics, who was not involved in the research, told Health.
To understand how dietary habits and other lifestyle factors impact risk, scientists analyzed data from 927,130 Japanese adults over age 20 enrolled in a medical database called DeSC. Participants filled out a lifestyle questionnaire during a health checkup and were followed for an average of 2.6 years to see if they developed an osteoporotic fracture.
After crunching the numbers, the researchers found that:
- People who reported skipping breakfast more than three times a week were 18% more likely to develop fractures.
- Those who said they ate dinner less than two hours before bedtime over three times a week were 8% more likely to develop fractures.
“We also observed that these dietary habits tended to cluster with other unhealthy behaviors, such as smoking, low physical activity, and insufficient sleep,” Hiroki Nakajima, MD, PhD, the study’s first author and a researcher at Nara Medical University in Japan, told Health.
If you tend to forego breakfast and eat dinner late, are the findings cause for concern? Not necessarily, experts agree.
While the study is “robust,” according to Nancy E. Lane, MD, a rheumatologist and professor of medicine at UC Davis who wasn’t involved in the research, it does have limitations. For instance, it didn’t measure other factors that may have influenced the results, such as the quantity or type of food participants ate.
“Evidence shows that low weight anorexia reduces peak bone mass, which is the No. 1 factor that you can modify to reduce risk of fracture in later years,” said Lane. “This information wasn’t collected, but eating disorders are well known to reduce bone mass and increase risk of fracture.”
Another caveat: The study is observational. That means it can show a link between eating patterns and fracture risk, but it can’t prove causation.
And while Nakajima believes the findings could apply beyond Japan—other research has shown that skipping breakfast and eating late are linked to obesity, diabetes, and other conditions in many countries, she noted—Gentile pointed out that Japan’s unique dietary patterns may limit how broadly the results can be applied.
Again, the research isn’t definitive. But experts have a few theories about how these dietary habits might influence osteoporosis risk.
One possible explanation involves the body’s circadian rhythm (or 24-hour clock), which plays a role in bone health, Lane said. “It’s possible that the individuals who skipped breakfast and/or ate a late dinner had less time to utilize these nutrients to remodel and form bone,” she noted.
Skipping breakfast might also increase levels of the stress hormone cortisol, negatively impacting bone health, she speculated.
For now, though, meal timing isn’t the primary focus when it comes to bone health. Instead, what you eat may matter more than when you eat it.
“In general,” Lane said, “we suggest a healthy diet with calcium, vitamin D, protein, and carbohydrates to allow the bone to remodel and remain strong.”
