Fiber Intake May Reduce Depression Risk in Women

A high-fiber diet may have a considerable impact on reducing symptoms of depression in women, according to a recent study in the journal Menopause.??

Researchers looked at three different years in a major, ongoing study in South Korea and selected about 5,800 women who had provided information on their dietary fiber intake and other health markers, including depression symptoms.

They found that, among premenopausal women, dietary fiber intake was higher in the non-depression group than in those who reported depression. However, among postmenopausal women, there was no significant difference.

Although this suggests there’s a correlation, not causation, this is not the first study to connect lower depression incidence and dietary fiber intake among premenopausal women. Research in Frontiers in Neuroscience?? that looked at over 3,000 women aged 42-52 came to the same conclusion: the higher the fiber intake, the less likely women were to report depressive symptoms.

Microbiome Role

The link between fiber intake and mental health is not a surprising one, according to the recent study’s lead author, Jung Ha Kim, MD, PhD, associate professor at Chung-ang University College of Medicine in South Korea.

Previous studies have found that fiber can improve the diversity of the gut microbiota, she says, and this could have a major effect on what’s called the “gut-brain axis.”

“Consider the fact that about 90% of your body’s serotonin is made in the gut,” adds dietitian Mary Purdy, RDN, author of The Microbiome Diet Reset. “Serotonin, which is a neurotransmitter, is important for your overall feeling of wellbeing and emotional health. So, if your serotonin production is affected by poor diet choices, it makes sense that your emotional health would be affected.”

In terms of why this effect isn’t seen as much with postmenopausal women, that is an area for further investigation, researchers noted. It could be because the issue is more complicated after menopause, due to hormonal changes, particularly with estrogen.

For example, a study in Frontiers in Microbiology?? noted that increased weight around the midsection—a common part of menopause—could be a confounding factor in the gut-brain axis.

Ripple Effect

Another advantage to eating more fiber is potentially lower cardiovascular risks. This is important for postmenopausal women because this type of risk increases after menopause, according to the American Heart Association.

Fiber helps reduce the body’s absorption of “bad” cholesterol and prompts better regulation of blood sugar—both of which can have a major impact on heart function.

Better heart health is another factor for lowering depression prevalence, according to a study in JAMA Psychiatry,?? which found a strong association between mental distress and cardiovascular disease. That connection goes both ways, says Ian Sadler, PhD, psychologist at Columbia University Irving Medical Center.

"Mental and emotional issues can affect physiological reactions, and vice versa," he says. "For example, we often see people with compromised immune function and chronic health problems facing mental health challenges. Addressing physical health will have an impact on mental wellbeing."

What to Eat

Much like its beneficial effect on the gut, fiber’s role for brain and heart health can be significant.

Purdy recommends focusing on whole-food options first, rather than relying on supplements immediately, since dietary sources are also packed with vitamins and minerals, and even some amount of protein and healthy fat. For example, consider these choices:

• Avocado
• Apples
• Berries
• Green leafy vegetables
• Oats
• Cruciferous vegetables
• Artichokes
• Beans
• Quinoa
• Nuts
• Sweet potatoes

Even dark chocolate has some fiber, at 3.1 grams in a 1-ounce piece.

Just adding one or two extra servings of fiber-rich foods per day can be a good first step, Purdy suggests.