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Disclosures: The authors report no relevant financial disclosures.
March 04, 2021
2 min read

‘Prudent’ diet may counteract detrimental effect of sitting on glucose levels

Disclosures: The authors report no relevant financial disclosures.
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A diet centered on fruits and vegetables is associated with lower 2-hour plasma glucose levels and may attenuate higher levels seen with prolonged sitting, such as when watching TV, according to study data.

“Lifestyles are most likely to interact with each other,” Tina Cao, MD, PhD, a research fellow at the Baker Heart and Diabetes Institute and the University of Melbourne in Victoria, Australia, told Healio. “With more convenient modern lifestyle, it is inevitable sometimes to have increased sitting time. We already know that prolonged sitting time is harmful to your glucose metabolism, but it is not the end of the world. If you can improve your diet to be healthier, it might alleviate the adverse effect on glucose with sitting time.”

TV Watching
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Cao and colleagues analyzed the TV viewing habits and dietary patterns of 3,081 adults who participated in the Australian Diabetes, Obesity and Lifestyle Study. Dietary intake was measured through a semiquantitative food frequency questionnaire examining consumption over 12 months of 74 food and beverage items using a 10-point frequency scale. Three dietary patterns were identified: a Western pattern with take-away foods, snacks, processed meat and red meat; a mixed pattern focused on fish, cereals, pasta, rice and poultry; and a “prudent” diet consisting primarily of fruits and vegetables. Each participant’s dietary factor scores were divided into quartiles based on their distribution in each dietary pattern.

Participants self-reported the amount of active TV viewing time. A 2-hour oral glucose tolerance test was conducted after an overnight fast, and information on sociodemographic and lifestyle habits, such as physical activity, smoking and alcohol consumption, was collected. The findings were published in the Journal of Diabetes.

The study cohort had a median fasting plasma glucose of 5.3 mmol/L and a 2-hour plasma glucose of 5.4 mmol/L. The mean TV viewing time was 1.8 hours per day, with 33% of participants watching more than 2 hours of TV daily.

Participants who were in the highest quartile for a prudent dietary pattern had a lower 2-hour plasma glucose level compared with those in the lowest quartile (5.2 mmol/L vs. 5.6 mmol/L; P = .001). In a model adjusted for age, sex, occupation, physical activity, education, marital status, total energy intake, smoking, waist circumference and family history of diabetes, TV viewing was positively associated with 2-hour plasma glucose, whereas a prudent dietary pattern was inversely associated with 2-hour plasma glucose in unadjusted and adjusted models.

“We were expecting that the Western dietary pattern — the unhealthier one — may increase the level of glucose,” Cao said. “But we found the opposite, that the prudent dietary pattern — the healthier one — actually protects against high glucose. This also makes sense as healthier diets often have been shown to have high level of antioxidant, which is helpful to reduce oxidative stress in beta-cell and the whole metabolic function.”

No association was found between any dietary patterns and fasting glucose, except for an association in the two highest quartiles of a mixed dietary pattern in unadjusted and adjusted models. In the fully adjusted model, participants with low TV viewing who were in the highest quartile of a prudent dietary pattern had the lowest 2-hour plasma glucose level.

“Clinicians might find the results are too marginal, as the magnitude is not too big,” Cao said. “However, as the study participants were all free of diabetes, the evidence has shown that even a little bit of change in glucose reduction, even in people with normal glucose level, can reduce the risk of developing diabetes and other cardiometabolic disorders. Clinicians may provide more advice on how to balance a healthy lifestyle in patients [with diabetes] or even in people with normal glucose level.”

For more information:

Tina Cao, MD, PhD, can be reached at tina.cao@unimelb.edu.au.