Trans fatty acid intake and risk of type 2 diabetes in the NutriNet-Santé prospective cohort

 

Type 2 diabetes (T2D) is one of the most common noncommunicable diseases worldwide, with an increasing prevalence and a considerable global health burden. Substantial evidence has linked consumption of trans fatty acids (TFAs) to an increased risk of cardiovascular disease. However, the effects of T2D remain unclear. We aimed to investigate the associations between different types of TFAs (total, ruminant, industrial and corresponding specific isomers) and risk of T2D in the NutriNet-Santé prospective cohort. Overall, 105,551 participants aged 18 years or older from the French NutriNet-Santé cohort (2009-2021) were included (mean age at baseline=42.7y (SD = 14.6y), 79.2% women). Dietary intake data, including usual TFA intake, were collected using repeated 24-hour dietary records (n = 5.7 [SD = 3.1]). Associations between sex-specific quartiles of dietary intake of TFAs and type 2 diabetes risk were assessed using multivariable Cox proportional hazard models adjusted for known risk factors. A total of 969 incident type 2 diabetes cases occured during follow-up. Total TFAs was associated with higher T2D risk (HRfor quartile 4 versus 1=1.38; 95% CI = 1.11-1.73; Ptrend<0.001). This association, specifically observed for industrial TFAs (HR = 1.45; 95% CI = 1.15-1.83; Ptrend<0.001), was mainly driven by elaidic acid (HR = 1.37; 95% CI = 1.09-1.72; Ptrend<0.001) and linolelaidic acid (HR = 1.29; 95% CI = 1.04-1.58; Ptrend=0.07). In contrast, ruminant trans fatty acids were not significantly associated with the risk of T2D. In this large prospective cohort, higher dietary intakes of total and industrial TFAs were associated with increased T2D risk. These findings support WHO's recommendation to eliminate industrially-produced TFAs from the food supply worldwide. As such, consumers should be advised to limit the consumption of food products containing partially hydrogenated oils (main vector of iTFAs) as this, specifically, may contribute to lower the substantial global burden of T2D.

Key messages

• Higher dietary intakes of total and industrial trans fatty acids were associated with increased type 2 diabetes risk.

• Our findings support WHO’s recommendation to eliminate industrially-produced TFAs from the food supply worldwide.

Dietary trans fatty acid intakes and cancer risk: results from the NutriNet-Santé cohort

 

Dietary trans fatty acids (TFAs) are either natural (ruminant sources) or industrially generated by partial hydrogenation of vegetable oils. Increasing evidence demonstrated their role as cardiovascular risk factors. Their involvement in cancer etiology is suspected, but epidemiological evidence is limited so far. We aimed to investigate the associations between different types of TFAs (total, ruminant [rTFAs], industrial [iTFAs] and corresponding specific isomers) and the risk of cancer in the NutriNet-Santé prospective cohort (2009-2020). Overall, 104,909 participants were included. Usual TFA intake was estimated from validated repeated 24-h dietary records. Associations between sex-specific quartiles of dietary intake of TFA and cancer risk were assessed using multi-adjusted Cox proportional hazard models. A total of 3,374 incident cancer cases occured during follow-up (including 982 breast and 405 prostate cancers). Total TFAs was associated with higher prostate cancer risk (1.34[1.25;1.87] Ptrend=0.005). rTFAs were associated with increased overall cancer risk (HRfor quartile 4 versus 1: 1.21[1.06;1.39] Ptrend=0.03), in particular the conjugated linoleic acid isomer (CLA) (1.19[1.04;1.36] Ptrend=0.04). These associations were specifically observed for breast cancer, in particular before menopause (rTFAs: 1.78[1.11;2.87] Ptrend=0.006; CLA: 2.013[1.25;3.23] Ptrend=0.003). Several iTFAs were associated with overall (1.18[1.06;1.31] Ptrend=0.02 for transdocosenoic acid), breast (isomer 18:2t: 1.30[1.06;1.58] Ptrend=0.01; hexadecenoic acid: 1.28[1.05-1.56] Ptrend=0.02) and prostate (transdocosenoic acid: 1.52[1.09;2.12] Ptrend=0.07) cancer risks. In this large prospective study, several types of TFAs were associated with increased overall, breast and prostate cancer risks. Although further studies are needed to better understand underlying mechanisms, these results support the WHO's goal of achieving industrially produced TFAs elimination from food supplies.

Key messages

Higher intake of dietary trans fatty acids is associated with an increased risk of various cancers. Our findings support WHO’s global recommendation of eliminating industrially produced TFAs by 2023.

The Role of Diet, Physical Activity, Body Fatness, and Breastfeeding in Breast Cancer in Young Women: Epidemiological Evidence

The incidence of breast cancer (BC) is rising worldwide, with an increase in aggressive neoplasias in young women. Traditionally, BC in young women has been thought to be etiologically driven, primarily by genetic/hereditary factors. However, these factors explain only a small proportion of BCs, pointing to a role of the environment. Suspected factors responsible for this increase include lifestyle changes, notably alcohol consumption, diet with high intake of refined carbohydrates and saturated fat and low intake of polyunsaturated fatty acids (PUFA), fiber and vitamins (such as folate, vitamin D, and carotenoids), low physical activity, and body fatness, all of which may act from childhood and adolescent years through adulthood. Despite limited data on BC in young women, evidence points to the importance of a healthy lifestyle, including high intake of vegetables, fruits, legumes, fish, and poultry, low intake of sugar and fat, daily physical activity, low alcohol consumption, steady weight, and breastfeeding in preventing BC in young women. Preventive efforts should begin in early life to provide important benefits much later in life by shifting the long-term trajectory of risk accumulation. Data from Latin America and developing regions are still sparse. There is a need to harmonize studies in a global effort to fight the rise of BC incidence in low- and middle-income countries, where the nutritional transition is occurring rapidly. The stratification of BC by specific tumor characteristics needs to be considered since risk factors may be more particularly associated with the promotion of, or protection from, a defined type of BC.

Dietary folate intake and breast cancer risk: European prospective investigation into cancer and nutrition

BACKGROUND

There is limited evidence on the association between dietary folate intake and the risk of breast cancer (BC) by hormone receptor expression in the tumors. We investigated the relationship between dietary folate and BC risk using data from the European Prospective Investigation into Cancer and Nutrition (EPIC).

METHODS

A total of 367993 women age 35 to 70 years were recruited in 10 European countries. During a median follow-up of 11.5 years, 11575 women with BC were identified. Dietary folate intake was estimated from country-specific dietary questionnaires. Cox proportional hazards regression models were used to quantify the association between dietary variables and BC risk. BC tumors were classified by receptor status. Subgroup analyses were performed by menopausal status and alcohol intake. Intake of other B vitamins was considered. All statistical tests were two-sided.

RESULTS

A borderline inverse association was observed between dietary folate and BC risk (hazard ratio comparing top vs bottom quintile [HRQ5-Q1] = 0.92, 95% CI = 0.83 to 1.01, P trend = .037). In premenopausal women, we observed a statistically significant trend towards lower risk in estrogen receptor-negative BC (HRQ5-Q1 = 0.66, 95% CI = 0.45 to 0.96, P trend = .042) and progesterone receptor-negative BC (HRQ5-Q1 = 0.70, 95% CI = 0.51 to 0.97, P trend = .021). No associations were found in postmenopausal women. A 14% reduction in BC risk was observed when comparing the highest with the lowest dietary folate tertiles in women having a high (>12 alcoholic drinks/week) alcohol intake (HRT3-T1 = 0.86, 95% CI = 0.75 to 0.98, P interaction = .035).

CONCLUSIONS

Higher dietary folate intake may be associated with a lower risk of sex hormone receptor-negative BC in premenopausal women.

Oral contraceptives, reproductive history and risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition

BACKGROUND

Oral contraceptive use and reproductive factors may initiate long-term changes to the hormonal milieu and thereby, possibly influence colorectal cancer risk.

METHODS

We examined the association of hormonal and reproductive factors with risk of colorectal cancer among 337,802 women in the European Prospective Investigation into Cancer and Nutrition, of whom 1878 developed colorectal cancer.

RESULTS

After stratification for center and age, and adjustment for body mass index, smoking, diabetes mellitus, physical activity and alcohol consumption, ever use of oral contraceptives was marginally inversely associated with colorectal cancer risk (hazard ratio (HR), 0.92; 95% confidence interval (CI), 0.83-1.02), although this association was stronger among post-menopausal women (HR, 0.84; 95% CI: 0.74-0.95). Duration of oral contraceptive use and reproductive factors, including age at menarche, age at menopause, type of menopause, ever having an abortion, parity, age at first full-term pregnancy and breastfeeding, were not associated with colorectal cancer risk.

CONCLUSION

Our findings provide limited support for a potential inverse association between oral contraceptives and colorectal cancer risk.

General and abdominal adiposity and risk of death in Europe

BACKGROUND

Previous studies have relied predominantly on the body-mass index (BMI, the weight in kilograms divided by the square of the height in meters) to assess the association of adiposity with the risk of death, but few have examined whether the distribution of body fat contributes to the prediction of death.

METHODS

We examined the association of BMI, waist circumference, and waist-to-hip ratio with the risk of death among 359,387 participants from nine countries in the European Prospective Investigation into Cancer and Nutrition (EPIC). We used a Cox regression analysis, with age as the time variable, and stratified the models according to study center and age at recruitment, with further adjustment for educational level, smoking status, alcohol consumption, physical activity, and height.

RESULTS

During a mean follow-up of 9.7 years, 14,723 participants died. The lowest risks of death related to BMI were observed at a BMI of 25.3 for men and 24.3 for women. After adjustment for BMI, waist circumference and waist-to-hip ratio were strongly associated with the risk of death. Relative risks among men and women in the highest quintile of waist circumference were 2.05 (95% confidence interval [CI], 1.80 to 2.33) and 1.78 (95% CI, 1.56 to 2.04), respectively, and in the highest quintile of waist-to-hip ratio, the relative risks were 1.68 (95% CI, 1.53 to 1.84) and 1.51 (95% CI, 1.37 to 1.66), respectively. BMI remained significantly associated with the risk of death in models that included waist circumference or waist-to-hip ratio (P<0.001).

CONCLUSIONS

These data suggest that both general adiposity and abdominal adiposity are associated with the risk of death and support the use of waist circumference or waist-to-hip ratio in addition to BMI in assessing the risk of death.

Influence of LDL oxidation on the proliferation of human breast cancer cells

The effects of lipid peroxidation and the antioxidant vitamin E contained in LDL isolated from control plasma (LDL--) and from plasma preincubated with 0.5 mmol/ml alpha-tocopherol (LDL+) on the proliferation of estrogen-receptor positive (ER+ : ZR-75, T-47-D, MCF-7) and negative (ER--: HBL-100, MDA-MB-231) human breast cancer cells were studied. Human skin fibroblasts served as controls. Incubation of plasma with 0.5 mmol/ml alpha-tocopherol resulted in a 3-fold increase of its content and a significant reduction in lipid hydroperoxides and conjugated dienes in LDL. Incubation of fibroblasts or ER+ tumor cells with LDL- or LDL+ had an effect on neither cell proliferation nor on the cellular levels of peroxidation products as compared to control incubations in the absence of LDL. In ER- cells, however, LDL+ stimulated the proliferation, whereas LDL- yielded a cytotoxic effect. Moreover, LDL- supplementation resulted in an increase in the content of hydroperoxides and conjugated dienes. LDL+ supplemented cells exhibited hydroperoxide levels in these tumor cells comparable to the basal levels measured in the absence of LDL. Our data suggested that peroxidation products in LDL are cytotoxic to estrogen-receptor negative breast tumor cells and vitamin E counteracts this effect.

Prognostic significance of tumor phosphatidylcholine stearic acid level in breast carcinoma

The involvement of lipid enzymes in the action of oncogenes at the cell membrane level has suggested that membrane lipids could play a role in modulating the growth of tumors. We previously found that breast cancer patients with a low level of polyunsaturated fatty acids in their primary tumor's phosphatidylethanolamine had a high risk of early occurrence of visceral metastasis. In the present study, we prospectively examined whether fatty acid composition of tumor membrane phosphatidylcholine had a prognostic significance in a series of 63 patients with a localized presentation of breast cancer. Membrane phospholipids were extracted from the carcinoma tissue obtained at the time of surgery, phosphatidylcholine was purified, and its fatty acids were analyzed by capillary gas chromatography. During the follow-up period, 20 patients developed metastasis. In these patients, the proportion of stearic acid containing phosphatidylcholine was significantly lower than it was in the tumors of the 43 patients who remained metastasis-free. Multivariate analysis according to Cox showed that low stearic acid level in tumor phosphatidylcholine and high mitotic index were independently predictive of subsequent metastasis. The predictive value of stearic acid level on metastasis risk was higher in node-positive patients than in node-negative patients, allowing individualization of a subgroup of low stearic acid level, node-positive patients with very poor prognosis. We concluded that stearic acid level in tumor membrane phosphatidylcholine is an independent intra-tumor marker of breast cancer prognosis. This finding is new evidence that tumor's structural lipids are linked to the growth of breast cancer.

Fatty-acid composition of breast and iliac adipose tissue in breast-cancer patients

In order to determine to what extent the fatty-acid composition of breast adipose tissue is representative of the body-fat composition in breast carcinoma, we compared the fatty-acid composition of breast adipose tissue to that of iliac fat in breast-cancer patients. Triglycerides from the 2 sites were purified by thin-layer chromatography and fatty-acid composition was determined by capillary gas chromatography. Compared with iliac fat, mammary fat was higher in saturated (33.2 +/- 3.9 vs. 24.4 +/- 1.6%; p = 0.0001) and lower in mono-unsaturated (48.0 +/- 2.2 vs. 54.8 +/- 2.7%; p = 0.0001) and poly-unsaturated fatty acids (16.6 +/- 3.7 vs. 18.0 +/- 3.1%; p = 0.0001). A positive correlation was found between the 2 sites for linoleate (r = 0.95; p = 0.0003), alpha-linolenate (r = 0.83; p = 0.01), palmitate (r = 0.78; p = 0.02) and palmitoleate (r = 0.76; p = 0.02). No relationship was observed for stearic and oleic acids. We conclude that breast and iliac fat differ with regard to fatty-acid composition. The interpretation of fatty-acid composition of the body stores in breast-cancer patients, as an indicator of long-term intake of dietary fat, should take into account the sampling site of stored lipids.

Glucuronidation of 2-arylpropionic acids pirprofen, flurbiprofen, and ibuprofen by liver microsomes

Acylglucuronide formation from the 2-arylpropionic acids pirprofen, flurbiprofen, and ibuprofen, three nonsteroidal anti-inflammatory drugs (NSAIDs), was investigated in rat liver microsomes using an HPLC method and 14C-labeled UDP-glucuronic acid as co-substrate. Pirprofen was the best substrate of UDP-glucuronosyltransferase with a Vmax/Km of 45.4, as compared with 8.0 and 1.6 for flurbiprofen and ibuprofen, respectively. Glucuronidation of the drugs was significantly increased upon treatment of rats with phenobarbital; 3-methylcholanthrene or clofibrate failed to induce the activity. At the dose of 100 mg/kg body weight for 1, 3, and 5 days, pirprofen was unable to induce its own glucuronidation. However, this treatment caused a transient increase, after 1 day, of several isoform activities monitored with 4-nitrophenol, 1-naphthol, 4-methylumbelliferone, terpenes, and testosterone as substrates. After 3 and 5 days these activities were decreased, especially when glucuronidation of 4-nitrophenol and 4-methylumbelliferone was considered, glucuronidation of the terpenes cis-myrtanol, borneol, nopol, and of testosterone being similar to control values. By contrast to clofibrate, administration of pirprofen to rats decreased bilirubin UDP-glucuronosyltransferase in a time-dependent fashion with a maximal decrease of 59% after 5 days. Treatment of rats with pirprofen also decreased markedly the formation of flurbiprofen glucuronide. Comparison of NSAID glucuronidation between several species indicated that it was most potent in monkeys, dogs, and humans. Cats were also efficient in that respect. Gunn rats, which are genetically deficient in bilirubin glucuronidation, were able to form acylglucuronides from the drugs, thus indicating that these 2-arylpropionic acids were not substrates of the bilirubin isozyme.