Field Notes

How Better Planning, Behavior Regulation May Lead to Eating Less Fat

New research suggests coaching pregnant women who are overweight or obese to improve their ability to plan and make progress toward goals may be key to helping them lower the amount of fat in their diet.

Maternal diet quality affects prenatal development and long-term child health outcomes, but the stress that typically increases during pregnancy—often heightened by concern for fetal health and anxiety over impending parenthood—may derail efforts to focus on healthful eating, previous research has shown.

In this new study, researchers at The Ohio State University set out to identify the pathway between stress and total fat consumption, with a broader goal to evaluate an intervention designed to improve the diets of pregnant women who are overweight or obese.

The study was published recently in the Journal of Pediatrics, Perinatology and Child Health.

Through a series of questionnaires and statistical analysis, the team found that two thinking-related skills—planning and execution of those plans—were weakened in women whose stress was high, and those skill gaps were associated with higher total fat intake.

These two skills are known as executive functions, a set of multiple thinking processes that enable people to plan, monitor behavior, and execute their goals.

“People with a higher level of stress tend to have a higher intake of fat, too. If stress is high, we’re so stressed out that we’re not thinking about anything—and we don’t care what we eat,” says lead author Mei-Wei Chang, PhD, RN, FAAN, an associate professor of nursing at Ohio State.

“That’s why we focused on executive functions as a mediator between stress and diet. And with this baseline data, we have reasons to believe that designing an intervention around executive functions could improve dietary outcomes,” she says. “I would anticipate the results could be similar for nonpregnant women because it’s all about how people behave.”

The 70 women enrolled in the study had a prepregnancy BMI of between 25 (scores between 25 and 29.9 are categorized as overweight) and 45 (scores of 30 and higher are categorized as obese).

The participants completed questionnaires assessing both overall perceived stress and pregnancy-related stress, as well as executive functions—specifically focusing on metacognition, or the ability to plan, and behavior regulation, the ability to execute those plans. They also completed two 24-hour dietary recalls of their calorie intake and consumption of total fat, added sugars, and fruits and vegetables.

“We were really interested in the mediation role of executive functions. The mediator is what makes everything happen,” Chang says. “We wanted to know: If we focus an intervention on executive functions, would that carry through to behavior change in dietary intake?

“Weight loss interventions often involve a prescribed diet or meal plan, and you’re told to follow it. But that doesn’t lead to behavior change in the long term.”

Statistical modeling showed that higher perceived stress was associated with a worsened ability to plan and monitor behavior, and that pathway was linked to higher total fat intake. Similarly, higher levels of pregnancy-related stress were associated with a lower ability to plan, which in turn was associated with worsened ability to monitor behaviors related to carrying out the plan—and these factors were linked to higher fat consumption.

These pathways suggested that an intervention designed to lower stress would function as a starting point to improve the diet and enhancing skills through coaching—emphasizing the ability to plan, including being flexible with planning, and behavior monitoring, particularly when making food choices—would be key to changing eating patterns.

“You need to improve executive functions, and you also need to lower stress,” Chang says. She and colleagues are now analyzing data on the effectiveness of an intervention for the study participants that emphasized stress management and boosting executive function to promote healthful eating.

Executive functions are regulated by a specific region of the brain, and strengths or weaknesses in these skill areas are thought to be affected by a variety of physiological factors. Previous research has found that executive function deficits are more likely to occur in women who are overweight or obese than in women whose weight is categorized as normal.

“Executive function isn’t well-studied, and it’s not related to intelligence. But people with low executive function are unable to make detailed plans and stick to them, and that’s how they get into trouble,” Chang says. “Metacognition and behavior regulation must go hand in hand—that way you have a much better chance to control your behaviors, and then you will eat better.”

— Source: Ohio State University


Fewer Cases of Melanoma Among People Taking Vitamin D Supplements

Vitamin D plays a key role in the normal function of the human body, and it also may play a role in many diseases. The link between vitamin D and skin cancers has been studied abundantly in the past, but these studies mainly have focused on serum levels of calcidiol, which is a metabolite of vitamin D, and its association with skin cancers. Findings from these studies have been inconclusive and even contradictory at times, as serum calcidiol levels have been associated with both a slightly higher and a slightly lower risk of different skin cancers. This may, in part, be explained by the fact that serum calcidiol analyses don’t provide information on the metabolism of vitamin D in the human skin, which can express enzymes that generate biologically active vitamin D metabolites or inactivate them.

The new study, conducted under the North Savo Skin Cancer Programme, took a different approach: 498 adult patients estimated to have an increased risk of a skin cancer, such as basal cell carcinoma, squamous cell carcinoma or melanoma, were recruited at the dermatological outpatient clinic of Kuopio University Hospital. Experienced dermatologists at the University of Eastern Finland carefully analyzed the patients' background information and medical history and examined their skin. The dermatologists also classified the patients into different skin cancer risk classes, namely low risk, moderate risk, and high risk. Based on their use of oral vitamin D supplements, the patients were divided into three groups: nonusers, occasional users, and regular users. Serum calcidiol levels were analyzed in one-half of the patients and found to correspond to their self-reported use of vitamin D.

A key finding of the study is that there were considerably fewer cases of melanoma among regular users of vitamin D than among nonusers and that the skin cancer risk classification of regular users was considerably better than that of nonusers. Logistic regression analysis showed that the risk of melanoma among regular users was considerably reduced, more than halved, compared with nonusers.

The findings suggest that even occasional users of vitamin D may have a lower risk of melanoma than nonusers. However, there was no statistically significant association between the use of vitamin D and the severity of photoaging, facial photoaging, actinic keratoses, nevus count, basal cell carcinoma, and squamous cell carcinoma. Serum calcidiol levels weren’t significantly associated with these skin changes, either. Since the research design was cross-sectional, the researchers were unable to demonstrate a causal relationship.

Other relatively recent studies, too, have provided evidence of the benefits of vitamin D in melanoma, such as the association of vitamin D with a less aggressive melanoma.

"These earlier studies back our new findings from the North Savo region here in Finland. However, the question about the optimal dose of oral vitamin D in order for it to have beneficial effects remains to be answered. Until we know more, national intake recommendations should be followed," says Ilkka Harvima, a professor of dermatology and allergology at the University of Eastern Finland.

Researchers at the University of Eastern Finland and Kuopio University Hospital previously have reported in a 2021 issue of BMC Cancer that the melanoma mortality rate in North Savo is relatively high in relation to its incidence.

"For this reason, too, it’s worth paying attention to sufficient intake of vitamin D in the population in this region," Harvima says.

— Source: University of Eastern Finland