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The impact of nutrition and lifestyle on male fertility.
Benatta, M, Kettache, R, Buchholz, N, Trinchieri, A
Archivio italiano di urologia, andrologia : organo ufficiale [di] Societa italiana di ecografia urologica e nefrologica. 2020;92(2)
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The impact of environmental, lifestyle and nutritional factors on unexplained male fertility has long been acknowledged. Yet, little research had been dedicated to the topic, despite declining semen quality having become a worldwide phenomena. Available studies have yielded limited, and at times conflicting, evidence. Hence this literature review sought to capture the current knowledge around unexplained male infertility and environmental, lifestyle, diet and nutrients factors. Summarized is the evidence from 69 studies, including population observations and clinical trials. The collected outcomes showed that a Western-type diet, rich in red and processed meats, refined grains, high-energy drinks and sweets, trans and saturated fats was associated with poor semen quality. Whereby higher intakes of fruits and vegetables, whole grains, omega-3 and poultry showed beneficial effects. However, as only selected groups were examined, more research is needed to project such findings onto the wider population. The reviewed evidence also included alcohol consumption, which showed high alcohol intake closely correlated to declining sperm concentrations. Whilst the verdict on caffeine consumption and the impact on sperm quality was inconclusive. In addition, several interventional studies evaluated the effect of dietary supplementation on various parameters of semen, where coenzyme Q10, L-carnitine, vitamin E, antioxidants, combined nutrient formulations and herbal blends all had positive outcomes. The review on zinc and folic acid supplementation yielded mixed results. This brief recap of the current evidence on environmental, lifestyle and nutritional influences on male infertility summarises the dietary foundations for the support of unexplained male infertility.
Abstract
BACKGROUND AND AIMS Male unexplained infertility has long been suspected to result from environmental, lifestyle and nutritional factors. However, the literature on the subject is still scarce, and clinical studies providing robust evidence are even scarcer. In addition, some similar studies come to different conclusions. Dietary pattern can influence spermatogenesis by its content of fatty acids and antioxidants. Yet, in an age of industrialized mass food production, human bodies become more exposed to the ingestion of xenobiotics, as well as chemicals used for production, preservation, transportation and taste enhancement of foods. We attempted in this paper to collect the available evidence to date on the effect of nutritional components on male fertility. MATERIAL AND METHODS A systematic search of the relevant literature published in PubMed, ScienceDirect and Cochrane Central Register of Controlled Trials Database was conducted. Literature was evaluated according to the Newcastle-Ottawa- Scale. RESULTS Epidemiological observations are concordant in demonstrating an association of low-quality sperm parameters with higher intake of red meat, processed and organ meat and fullfat dairy. On the contrary, better semen parameters were observed in subjects consuming a healthy diet, rich in fruit, vegetables, whole grains and fish. Evidences of the negative impact on male fertility of by-products of water disinfection, accumulation in food chain of persistent organochlorine pollutants, pesticides, phthalates from food and water containers and hormones used in breeding cattle have been reported. Clinical trials of the effects of micronutrients on semen parameters and outcomes of assisted fertilization are encouraging, although optimal modality of treatment should be established. CONCLUSIONS Although quality of evidence should be ameliorated, it emerges that environmental factors can influence male fertility. Some nutrients may enhance fertility whereas others will worsen it. With diagnostic analysis on a molecular or even sub-molecular level, new interactions with micronutrients or molecular components of our daily ingested foods and leisure drugs may lead to a better understanding of so far suspected but as yet unexplained effects on male spermatogenesis and fertility.
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Prospective association between organic food consumption and the risk of type 2 diabetes: findings from the NutriNet-Santé cohort study.
Kesse-Guyot, E, Rebouillat, P, Payrastre, L, Allès, B, Fezeu, LK, Druesne-Pecollo, N, Srour, B, Bao, W, Touvier, M, Galan, P, et al
The international journal of behavioral nutrition and physical activity. 2020;17(1):136
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The prevalence of type 2 diabetes (T2D) has significantly increased over recent decades, concomitantly to the obesity epidemic. Among the emergent risk factors, exposure to environmental contaminants including pesticides is of major concern. In fact, a recent European Food Safety Authority report indicated that 44% of conventional crop-based food contained at least one quantifiable pesticide residue, vs 6.5% in organic-labelled foods (OF). The aims of this study were (a) to investigate the prospective association between OF consumption and the risk of T2D, and (b) to estimate the mediation effect by the potential healthiness of a plant-based diet. This study is prospective cohort study based on the data from the web-based NutriNet-Santé study with an analysis sample of 33,256 participants. Results indicate an inverse association between organic plant-based food consumption and T2D risk especially in women. The association persisted after accounting for potential confounding effects of various factors, including lifestyles, dietary patterns and adiposity. Authors conclude that further studies are needed to replicate these findings for confirmation purposes and to elucidate underlying mechanisms.
Abstract
BACKGROUND Organic food (OF) consumption has substantially increased in high income countries, mostly driven by environmental concerns and health beliefs. Lower exposure to synthetic pesticides has been systematically documented among consumers of organic products compared to non-consumers. While experimental studies suggest that pesticides currently used in food production may be associated with type 2 diabetes (T2D), no well-conducted prospective studies have investigated the potential association between consumption of organic products and the risk of T2D, controlling for potential confounding factors. The objective of this prospective study was to estimate the association between OF consumption and the risk of T2D. METHODS A total of 33,256 participants (76% women, mean (SD) age: 53 years (14)) of the French NutriNet-Santé prospective cohort study who completed the organic food frequency questionnaire were included (2014-2019). The proportion of OF in the diet (as weight without drinking water) was computed. The associations between the proportion of OF in the diet (as 5% increment and as quintiles) and the risk of T2D were estimated using multivariable Hazard Ratio (HR) and 95% confidence interval (95% CI) derived from proportional hazards models adjusted for confounders (sociodemographic, anthropometric, lifestyle, medical and nutritional factors). RESULTS During follow-up (mean = 4.05 y, SD = 1.03 y, 134,990 person-years), 293 incident cases of T2D were identified. After adjustment for confounders including lifestyle (physical activity, smoking status, alcohol consumption) and nutritional quality of the diet assessed by the adherence to the French food-based dietary guidelines, OF consumption was associated with a lower risk of T2D. Participants with the highest quintile of OF consumption, compared with those with the lowest quintile, had 35% lower risk of T2D (95% CI = 0.43-0.97). Each increment of 5% in the proportion of OF in the diet was associated with 3% lower risk of T2D (HR 0.97, 95% CI = 0.95-0.99). CONCLUSIONS In this large prospective cohort study, OF consumption was inversely associated with the risk of T2D. Further experimental and prospective studies should be conducted to confirm these observations. CLINICAL TRIAL REGISTRY The study was registered at ClinicalTrials.gov ( NCT03335644 ).
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Consumption of ultra-processed foods and cancer risk: results from NutriNet-Santé prospective cohort.
Fiolet, T, Srour, B, Sellem, L, Kesse-Guyot, E, Allès, B, Méjean, C, Deschasaux, M, Fassier, P, Latino-Martel, P, Beslay, M, et al
BMJ (Clinical research ed.). 2018;360:k322
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Foods that are heavily processed tend to have high levels of total fat, sugar and salt and low levels of fibre and vitamins. They also tend to have high levels of contaminants (caused for example by high heat treatment), food additives and plastic packaging exposure. This large prospective population-based cohort study assessed the association between ultra-processed food consumption and the incidence of cancer. The study found that ultra-processed food intake was associated with a higher overall cancer risk and a higher breast cancer risk. A 10% increase in the consumption of ultra-processed foods was associated with an increase of more than 10% greater risk of overall and breast cancer risk. The authors call for further studies to better understand the different elements of food processing and their association to cancer risk.
Abstract
OBJECTIVE To assess the prospective associations between consumption of ultra-processed food and risk of cancer. DESIGN Population based cohort study. SETTING AND PARTICIPANTS 104 980 participants aged at least 18 years (median age 42.8 years) from the French NutriNet-Santé cohort (2009-17). Dietary intakes were collected using repeated 24 hour dietary records, designed to register participants' usual consumption for 3300 different food items. These were categorised according to their degree of processing by the NOVA classification. MAIN OUTCOME MEASURES Associations between ultra-processed food intake and risk of overall, breast, prostate, and colorectal cancer assessed by multivariable Cox proportional hazard models adjusted for known risk factors. RESULTS Ultra-processed food intake was associated with higher overall cancer risk (n=2228 cases; hazard ratio for a 10% increment in the proportion of ultra-processed food in the diet 1.12 (95% confidence interval 1.06 to 1.18); P for trend<0.001) and breast cancer risk (n=739 cases; hazard ratio 1.11 (1.02 to 1.22); P for trend=0.02). These results remained statistically significant after adjustment for several markers of the nutritional quality of the diet (lipid, sodium, and carbohydrate intakes and/or a Western pattern derived by principal component analysis). CONCLUSIONS In this large prospective study, a 10% increase in the proportion of ultra-processed foods in the diet was associated with a significant increase of greater than 10% in risks of overall and breast cancer. Further studies are needed to better understand the relative effect of the various dimensions of processing (nutritional composition, food additives, contact materials, and neoformed contaminants) in these associations. STUDY REGISTRATION Clinicaltrials.gov NCT03335644.