Hold the Fruit Juice, Please!

Choosing to eat whole fruits instead of drinking fruit juice could help reduce the risk of developing type 2 diabetes.

Increased insulin resistance and beta-cell dysfunction play a key role in developing type 2 diabetes (T2D). T2D causes more than 200 million deaths occur annually, and worldwide, it is the seventh primary source of disability. The sum of people to develop T2D is expected to surpass 693 million by the year 2045. The solid evidence behind minimizing the risk of T2D supports the encouragement of regular exercise and maintaining a healthy diet. Notably, fruit — not fruit juice — intake is inversely correlated with type 2 diabetes prevalence, as reported from three prospective longitudinal cohort studies. The Australian Dietary Guidelines recommend two servings (150g) of fruit consumed daily in adults, which is linked to a 32% risk reduction of T2D in the AusDiab study over 12 years.

Moreover, 23% of T2D cases may have been averted if individuals were adherent to the recommendations, as stated by the authors. However, not all fruit has similar protection against T2D; grapefruit, bananas, apples, grapes, and blueberries were independently linked to a decreased risk of T2D. In addition, the connection between fruit intake and insulin resistance and beta-cell dysfunction is yet to be entirely recognized.

The study’s intent by Bondonna et al. examined the correlation between total fruit intake, commonly consumed individual fruits, fruit juice, beta-cell dysfunction, insulin resistance, and occurrence of T2D at five and twelve-year follow-up in Australian women and men. Individuals were included in the study if they were ≥ 25 years, enrolled in the Australian Diabetes, Obesity, and Lifestyle Study (AusDiab cohort) from 1999 to 2000. The AusDiab cohort is a diabetes frequency and related risk factor survey in the Australian population. For the current study, 7675 patients were evaluated at baseline, 4674 were followed-up at five years, and 3518 at 12 years. Individual fruits and total fruit intake commonly consumed by the patients were considered the exposures of interest assessed at baseline by the food frequency questionnaire (FFQ). Fasting insulin levels at baseline, fasting plasma glucose (FPG), 2-hour post-load plasma glucose (PLG), homeostasis model assessment of beta-cell function (HOMA2-%β), and HOMA2 of insulin sensitivity (HOMA2-%S) were the primary outcomes evaluated by restricted cubic splines in logistic and linear regression models. The secondary outcome was T2D events at 5 and 12 years follow up.

The total Australian population of 7674 was 45% male, the mean age of 54 years at baseline, and the median total consumption of fruit was 162g per day. Compared to patients with total low fruit consumption, those with a higher total fruit consumption were females primarily of older age, had a more active lifestyle, had a higher level of education, were not likely to use tobacco, and were less underprivileged. These individuals also ate healthier, such as consuming vegetables and less processed and red meat, than patients with total low fruit intake. The fruit mostly eaten was apples (23% of total fruit intake) and had a notable inverse association with serum insulin (p=0.035) and nonlinearly inversely correlated with PLG. Bananas (approximately 20%) were the second most consumed, followed by oranges and other citrus fruits (approximately18%). Fruit juice, bananas, and citrus fruits had no substantial correlation with any outcome. The total fruit consumption was substantially inversely linked with HOMA2-%β and serum insulin and positively associated with HOMA2-%S. There was no relationship between FPG or PLG with total fruit intake. Persons with a higher fruit intake had a higher HOMA2-%S at 6%, a lower HOMA2-%β at 2%, lower serum insulin 5%, and a lower PLG 3%. At the five-year follow-up,179 persons had diabetes where total fruit intake presented with a nonlinear inverse association with the rate of T2M. Those with moderate fruit intake had lower odds (36%) of acquiring T2D than low fruit intake (OR 0.64). After adjusting for possible lifestyle and dietary confounders, the evident inverse associations for individual types of fruit were not statically significant. At the 12 years follow-up, 247 individuals who acquired T2D and OR were reduced in moderate fruit consumption; however, results were not statistically significant.

Practice Pearls

• Fruit juice does not aid in reducing the risk of developing type 2 diabetes. However, a nutritious diet consisting of whole fruit has been proven beneficial.
• Medium to high total ingestion of fruit was linked with a decreased probability of T2D after a five-year follow-up.
• Beta-cell dysfunction, insulin resistance, and obesity are the main factors of the pathophysiology of T2D. 

Bondonno, Nicola P et al. “Associations between fruit intake and risk of diabetes in the AusDiab cohort.” The Journal of clinical endocrinology and metabolism, dgab335. 2 Jun. 2021, doi:10.1210/clinem/dgab335. https://academic.oup.com/jcem/advance-article/doi/10.1210/clinem/dgab335/6290732

Muraki, Isao et al. “Fruit consumption and risk of type 2 diabetes: results from three prospective longitudinal cohort studies.” BMJ (Clinical research ed.) vol. 347 f5001. 28 Aug. 2013, doi:10.1136/BMJ.f5001. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3978819/

Trina Maglalang RPh, 2022 PharmD Candidate University of Colorado