Processed potatoes intake and risk of type 2 diabetes: a systematic review and meta-analysis of nine prospective cohort studies

Potatoes - a scoping review for Nordic Nutrition Recommendations 2023

Potatoes comprise a common staple food in the Nordic and Baltic countries and contribute to the diet with vitamins, minerals, dietary fibre and phytochemicals. However, potatoes may also be consumed in processed forms with added fat and salt, which raises concerns about possible adverse health effects. The aim of this scoping review is to describe the overall evidence for the role of potatoes as a basis for setting and updating food-based dietary guidelines in the Nordic Nutrition Recommendations 2023. PubMed was searched for systematic reviews and meta-analyses, and evidence was extracted on relevant health outcomes. Current available evidence indicates that moderate consumption of potatoes is not associated with a substantial risk of chronic diseases, and that they may be part of a healthy diet. However, the health effects vary greatly depending on cooking methods, and studies indicate that the intake of French fries/fried potatoes should be limited. Overall, the evidence regarding health effects of potatoes is very limited, and possible associations need to be further investigated.

Perspective: Potatoes, Quality Carbohydrates, and Dietary Patterns

Potatoes have long been a staple food in many cultures and cuisines, but they have gained a reputation as a low-quality carbohydrate source that should be avoided in the diet. Historically, this view has been justified by citing the glycemic index of potatoes as the main indicator of their quality. However, their nutrient composition should also be considered. The association of potatoes with energy-dense Western dietary patterns has also contributed to a perception that potatoes are inherently unhealthy. Although some studies have suggested an association between potato consumption and increased risk of health problems, such as type 2 diabetes, these associations may be confounded by fried potato intake and are strongest at intake levels higher than average consumption rates. Epidemiologic data suggest total potato intake is not a health risk in Eastern populations and can be consumed as part of a healthy diet. Furthermore, clinical trial data demonstrate that potatoes' health impact, irrespective of preparation, is similar to legumes and comparable with refined grains, with few deleterious effects found. These findings highlight the importance of moving beyond the glycemic index and adopting a more nuanced evaluation of the epidemiologic data to better understand the health impact of potato intake. Ultimately, the negative reputation of potatoes stems from an overinterpretation of their glycemic index and association with unhealthy Western dietary patterns, as well as oversimplification of the epidemiologic data. By considering carbohydrate quality, it becomes clear that potatoes can be part of a healthy diet given the proper consideration.

Potato consumption, polygenic scores, and incident type 2 diabetes: An observational study

Whether the consumption of different processed potatoes is detrimental to type 2 diabetes (T2D) is highly debated. This study aimed to assess the relations between potato consumption and the risk of T2D and whether the relationship was modified by the genetic predisposition to T2D. We included 174,665 participants from the UK Biobank at baseline. Potato consumption was evaluated using the 24-hour dietary questionnaire. The genetic risk score (GRS) was calculated based on 424 variants associated with T2D. After adjustment for demographic, lifestyle, and dietary factors, the consumption of total potatoes was significantly and positively associated with T2D risk [hazard ratio (HR) comparing two or more servings/day with non-consumers was 1.28 (95% CI: 1.13-1.45)]. HRs (95% CIs) of T2D for each 1-SD increment in boiled/baked potatoes, mashed potatoes, and fried potatoes were 1.02 (0.99-1.05), 1.05 (1.02-1.08), and 1.05 (1.02-1.09), respectively. There were no significant interactions between the consumption of total or different processed potatoes and overall GRS on T2D risk. Theoretically, replacing one serving/day of total potatoes with the same amount of non-starchy vegetables was related to a 12% (95% CI: 0.84-0.91) lower T2D risk. These results showed the positive associations of the consumption of total potatoes, mashed potatoes or fried potatoes and genetic risk with higher incident T2D. An unhealthy potato-based diet is associated with higher diabetes risk regardless of genetic risk.

Incident type 2 diabetes attributable to suboptimal diet in 184 countries

The global burden of diet-attributable type 2 diabetes (T2D) is not well established. This risk assessment model estimated T2D incidence among adults attributable to direct and body weight-mediated effects of 11 dietary factors in 184 countries in 1990 and 2018. In 2018, suboptimal intake of these dietary factors was estimated to be attributable to 14.1 million (95% uncertainty interval (UI), 13.8-14.4 million) incident T2D cases, representing 70.3% (68.8-71.8%) of new cases globally. Largest T2D burdens were attributable to insufficient whole-grain intake (26.1% (25.0-27.1%)), excess refined rice and wheat intake (24.6% (22.3-27.2%)) and excess processed meat intake (20.3% (18.3-23.5%)). Across regions, highest proportional burdens were in central and eastern Europe and central Asia (85.6% (83.4-87.7%)) and Latin America and the Caribbean (81.8% (80.1-83.4%)); and lowest proportional burdens were in South Asia (55.4% (52.1-60.7%)). Proportions of diet-attributable T2D were generally larger in men than in women and were inversely correlated with age. Diet-attributable T2D was generally larger among urban versus rural residents and higher versus lower educated individuals, except in high-income countries, central and eastern Europe and central Asia, where burdens were larger in rural residents and in lower educated individuals. Compared with 1990, global diet-attributable T2D increased by 2.6 absolute percentage points (8.6 million more cases) in 2018, with variation in these trends by world region and dietary factor. These findings inform nutritional priorities and clinical and public health planning to improve dietary quality and reduce T2D globally.

Can habitual tea drinking be an effective approach against age-related neurodegenerative cognitive disorders: A systematic review and meta-analysis of epidemiological evidence

Our present knowledge about the efficacy of tea consumption in improving age-related cognitive disorders is incomplete since previous epidemiological studies provide inconsistent evidence. This unified systematic review and meta-analysis based on updated epidemiological cohort studies and randomized controlled trials (RCTs) evidence aimed to overcome the limitations of previous reviews by examining the efficacy of distinct types of tea consumption. PubMed, Embase, and MEDLINE were searched up to May 20, 2022, and 23 cohorts and 12 cross-sectional studies were included. Random-effects meta-analyses were conducted to obtain pooled RRs or mean differences with 95% CIs. The pooled RRs of the highest versus lowest tea consumption categories were 0.81 (95% CIs: 0.75-0.88) and 0.69 (95% CIs: 0.61-0.77), respectively. The pooled mean difference of four included RCTs revealed a beneficial effect of tea on cognitive dysfunction (MMSE ES: 1.03; 95% CI, 0.14-1.92). Subgroup analyses further demonstrated that green and black tea intake was associated with a lower risk of cognitive disorders in eastern countries, especially in women. The evidence quality was generally low to moderate. The present review provides insight into whether habitual tea consumption can be an effective approach against age-related neurodegenerative cognitive disorders and summarizes potential mechanisms based on currently published literature.

Association of dietary meat consumption habits with neurodegenerative cognitive impairment: an updated systematic review and dose-response meta-analysis of 24 prospective cohort studies

The association between dietary meat consumption habits and neurodegenerative cognitive impairment (NCI) has been made but recent studies have reported controversial results. Herein, we have systematically explored associations between meat consumption and NCI risk. PubMed, Embase, and MEDLINE databases were explored for data sources of primary studies. Twenty-four prospective cohort studies that met the selection criteria, involving over 500 000 participants from 11 countries, were included. Relative risks (RRs) were pooled using random-effects model meta-analysis, and a dose-response analysis was conducted using a 2-stage generalized least-squares trend program. The results showed that total meat (RRs 1.14; 95% CI: 1.04-1.24), fish (RRs 0.87; 95% CI: 0.78-0.98), and poultry (RRs 0.88; 95% CI: 0.80-0.98) intake was significantly associated with NCI risk but red meat (RRs 1.03; 95% CI: 0.92-1.16) showed a non-significant association. Subgroup analysis further demonstrated a significant association between total meat consumption and the risk of NCI, especially for total processed meat (RRs 1.67; 95% CI, 1.46-1.92) and processed red meat (RRs 1.22; 95% CI, 1.11-1.34). Each additional 50 g day^-1 intake of total meat (RRs 1.03; 95% CI: 1.00-1.05) and processed meat (RRs 1.12; 95% CI: 1.08-1.17) increased the risk of NCI. In contrast, a 50 g day^-1 increment of fish (RRs 0.97; 95% CI: 0.94-0.99) and poultry (RRs 0.948; 95% CI: 0.90-0.99) intake was associated with lower NCI risk. This study provided evidence for further understanding the relationship between the type and amount of meat intake and the occurrence of NCI.

Scientific advice related to nutrient profiling for the development of harmonised mandatory front-of-pack nutrition labelling and the setting of nutrient profiles for restricting nutrition and health claims on foods

Following a request from the European Commission, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver scientific advice related to nutrient profiling for the development of harmonised mandatory front‐of‐pack nutrition labelling and the setting of nutrient profiles for restricting nutrition and health claims on foods. This Opinion is based on systematic reviews and meta‐analyses of human studies on nutritionally adequate diets, data from the Global Burden of Disease framework, clinical practice guidelines, previous EFSA opinions and the priorities set by EU Member States in the context of their Food‐Based Dietary Guidelines and associated nutrient/food intake recommendations. Relevant publications were retrieved through comprehensive searches in PubMed. The nutrients included in the assessment are those likely to be consumed in excess or in inadequate amounts in a majority of European countries. Food groups with important roles in European diets have been considered. The Panel concludes that dietary intakes of saturated fatty acids (SFA), sodium and added/free sugars are above, and intakes of dietary fibre and potassium below, current dietary recommendations in a majority of European populations. As excess intakes of SFAs, sodium and added/free sugars and inadequate intakes of dietary fibre and potassium are associated with adverse health effects, they could be included in nutrient profiling models. Energy could be included because a reduction in energy intake is of public health importance for European populations. In food group/category‐based nutrient profiling models, total fat could replace energy in most food groups owing to its high‐energy density, while the energy density of food groups with low or no fat content may be well accounted for by the inclusion of (added/free) sugars. Some nutrients may be included in nutrient profiling models for reasons other than their public health importance, e.g. as a proxy for other nutrients of public health importance, or to allow for a better discrimination of foods within the same food category.

Evaluation of the Quality of Evidence of the Association of Foods and Nutrients With Cardiovascular Disease and Diabetes: A Systematic Review

IMPORTANCE

Poor diet is a leading global factor associated with cardiometabolic disease (CMD). Understanding the quality of evidence of the associations between specific dietary factors and CMD, including effect size (relative risk [RR]) and uncertainty, is essential to guide policy and consumer actions to achieve healthy diet and public health goals.

OBJECTIVE

To assess the quality of evidence of the associations between specific dietary factors and CMD as well as the quantitative evidence for RRs and the uncertainty of these risk estimates.

EVIDENCE REVIEW

PubMed and the reference lists of eligible articles were searched between May 1, 2015, and February 26, 2021, for systematic reviews with meta-analyses of randomized clinical trials and prospective cohort studies that analyzed the consumption of 1 or more of the dietary factors of interest; reported dose-response meta-analyses; included healthy adults; and assessed 1 or more of the outcomes of interest. Study characteristics and RR estimates were extracted in duplicate. For identified associations, quality of evidence was assessed using the Bradford-Hill criteria for causation.

FINDINGS

A total of 2058 potentially relevant reports were identified, from which 285 full-text articles were assessed for eligibility. The final selection of articles included 28 meta-analyses representing 62 associations between diet and CMD. Among these associations, 10 foods, 3 beverages, and 12 nutrients had at least probable evidence of associations with coronary heart disease, stroke, and/or diabetes. Most RRs ranged from 0.87 to 0.96 per daily serving change for protective associations and from 1.06 to 1.15 per daily serving change for harmful associations. Most identified associations were protective (n = 38) and a smaller number were harmful (n = 24), with a higher risk associated with higher intake.

CONCLUSIONS AND RELEVANCE

This systematic review summarized the current quality of evidence of the associations of specific dietary factors with coronary heart disease, stroke, and diabetes. These findings may inform dietary guidance, the assessment of disease burden in specific populations, policy setting, and future research.