Impact of organic foods on chronic diseases and health perception: a systematic review of the evidence

The aim of the present systematic review was to evaluate the existing data on the health impacts, of the consumption of organically grown foods versus conventionally farmed alternatives, with specific focus on the postulated health superiority of organic foods. A systematic literature research was performed in PubMed, Embase, Web of Science, and Google Scholar. Inclusion criteria were articles on adults (>18 years of age) consuming organic foods for ≥6 months, written in English language, and provision of comparative results between conventional and organic nutrition regarding health indices. From 1760 identified references, 21 primary research articles (2006-2022) met the inclusion criteria. Outcomes related to chronic disease prevalence, biomarker effects, and exposure to pesticides and other harmful substances were evaluated. A significant inverse relationship between organic food consumption and cardiometabolic risk factors, including obesity, diabetes mellitus, hypertension, and hyperlipidemia, was observed in the majority of prospective studies. The data on cancer risk and nutrient value comparison between organic and conventional foods were inconclusive. Clinical trials consistently indicated lower pesticide exposure in participants on organic diets, suggesting potential health benefits. The consumption of organic foods is associated with reduced cardiometabolic risks and pesticide exposure. However, the long-term impact on cancer risk remains undetermined. Future long-term studies are needed to establish whether an organic diet is superior to a conventional one in terms of overall health benefits.

Fertilizer Type Affects Stable Isotope Ratios of Nitrogen in Human Blood Plasma─Results from Two-Year Controlled Agricultural Field Trials and a Randomized Crossover Dietary Intervention Study

The stable nitrogen isotope ratio δ¹⁵N is used as a marker of dietary protein sources in blood. Crop fertilization strategies affect δ¹⁵N in plant foods. In a double-blinded randomized cross-over dietary intervention trial with 33 participants, we quantified the effect of fertilizer type (conventional: synthetic fertilizer and organic: animal or green manure) on δ¹⁵N in blood plasma. At study baseline, plasma δ¹⁵N was +9.34 ± 0.29‰ (mean ± standard deviation). After 12 days intervention with a diet based on crops fertilized with animal manure, plasma δ¹⁵N was shifted by +0.27 ± 0.04‰ (mean ± standard error) compared to synthetic fertilization and by +0.22 ± 0.04‰ compared to fertilization with green manure (both p < 0.0001). Accordingly, differences in the δ¹⁵N values between fertilizers are propagated to the blood plasma of human consumers. The results indicate a need to consider agricultural practices when using δ¹⁵N as a dietary biomarker.

Increase of 4-Hydroxybenzoic, a Bioactive Phenolic Compound, after an Organic Intervention Diet

Consumption of organic products is increasing yearly due to perceived health-promoting qualities. Several studies have shown higher amounts of phytochemicals such as polyphenols and carotenoids in foods produced by this type of agriculture than in conventional foods, but whether this increase has an impact on humans still needs to be assessed. A randomized, controlled and crossover study was carried out in nineteen healthy subjects aged 18-40 years, who all followed an organic and conventional healthy diet, both for a 4-week period. Analysis of biological samples revealed a significant increase on the excretion of 4-hydroxybenzoic acid (4-HBA), a phenolic metabolite with biological activity, after the organic intervention. However, no changes were observed in the other variables analyzed.

Some Differences in Nutritional Biomarkers are Detected Between Consumers and Nonconsumers of Organic Foods: Findings from the BioNutriNet Project

BACKGROUND

Meta-analyses have compared the nutrient content of both organic and nonorganic foods. However, the impacts of such variations on human nutritional biomarkers still need to be assessed.

OBJECTIVE

In a nested clinical study from the NutriNet-Santé study, we aimed to compare the nutritional status of "organic" and "nonorganic" food consumers matched on a propensity score.

METHODS

Based on self-reported organic food consumption assessed through a food frequency questionnaire (FFQ), 150 low and 150 high organic food consumers were selected with <10% or >50% of organic food in their diet, respectively (expressed as the proportion of organic food in the whole diet in g/d). Participants were matched using a propensity score derived from socio-demographic, food, and health variables. Fasting plasma samples were analyzed using acknowledged laboratory methods for measurements of iron status, magnesium, copper, cadmium, carotenoids, vitamins A and E, and fatty acids.

RESULTS

We found significant differences between low and high organic food consumers with similar dietary patterns, with respect to plasma concentrations of magnesium, fat-soluble micronutrients (α-carotene, β-carotene, lutein, and zeaxanthin), fatty acids (linoleic, palmitoleic, γ-linolenic, and docosapentanoeic acids), and some fatty acid desaturase indexes. No differences between the 2 groups were detected for plasma concentrations of iron, copper, cadmium, lycopene, β-cryptoxanthin, or vitamins A and E.

CONCLUSION

If confirmed by other studies, our data suggest that a high consumption of organic foods, compared with very low consumption, modulates to some extent, the nutritional status of individuals with similar dietary patterns. Further research including prospective cohort studies is needed to evaluate the clinical relevance of such differences.

Socio-demographic, lifestyle, and dietary determinants of essential and possibly-essential trace element levels in adipose tissue from an adult cohort

There is increasing evidence linking levels of trace elements (TEs) in adipose tissue with certain chronic conditions (e.g., diabetes or obesity). The objectives of this study were to assess concentrations of a selection of nine essential and possibly-essential TEs in adipose tissue samples from an adult cohort and to explore their socio-demographic, dietary, and lifestyle determinants. Adipose tissue samples were intraoperatively collected from 226 volunteers recruited in two public hospitals from Granada province. Trace elements (Co, Cr, Cu, Fe, Mn, Mo, Se, V, and Zn) were analyzed in adipose tissue by high-resolution inductively coupled plasma mass spectrometry (HR-ICP-MS). Data were collected on socio-demographic characteristics, lifestyle, diet, and health status by face-to-face interview. Predictors of TE concentrations were assessed by using multivariable linear and logistic regression. All TEs were detected in all samples with the exception of Se (53.50%). Iron, zinc, and copper showed the highest concentrations (42.60 mg/kg, 9.80 mg/kg, and 0.68 mg/kg, respectively). Diet was the main predictor of Cr, Fe, Mo, and Se concentrations. Body mass index was negatively associated with all TEs (β coefficients = -0.018 to -0.593, p = 0.001-0.090) except for Mn and V. Age showed a borderline-significant positive correlation with Cu (β = 0.004, p = 0.089). Residence in a rural or semi-rural area was associated with increased Co, Cr, Fe, Mo, Mn, V and Zn concentrations and with β coefficients ranging from 0.196 to 0.544 (p < 0.05). Furthermore, individuals with higher educational level showed increased Cr, Co, Fe and V concentrations (β coefficients = 0.276-0.368, p = 0.022-0.071). This is the first report on the distribution of these TEs in adipose tissue and on their determinants in a human cohort and might serve as an initial step in the elucidation of their clinical relevance.

Organic food and the impact on human health

In the last decade, the production and consumption of organic food have increased steadily worldwide, despite the lower productivity of organic crops. Indeed, the population attributes healthier properties to organic food. Although scientific evidence is still scarce, organic agriculture seems to contribute to maintaining an optimal health status and decreases the risk of developing chronic diseases. This may be due to the higher content of bioactive compounds and lower content of unhealthy substances such as cadmium and synthetic fertilizers and pesticides in organic foods of plant origin compared to conventional agricultural products. Thus, large long-term intervention studies are needed to determine whether an organic diet is healthier than a diet including conventionally grown food products. This review provides an update of the present knowledge of the impact of an organic versus a conventional food diet on health.

Zinc Fractional Absorption from a Representative Diet in Young Chinese Men and Women of the Shandong Rural Region

The objective of this study was to investigate the zinc fractional absorption of young Chinese men and women from the Shandong rural region under the routine dietary pattern by stable isotope technique. Ten men and 10 women, aged 20 to 35 years, and with a representative diet during the experiment were recruited from the Shandong rural region. Stable 67Zn was used as a tracer to label ZnCl2, and Yb was used to monitor the excretion of 67Zn in urine and feces. All volunteers were given rice containing 4.0 mg 67Zn and 1.0 mg Yb on the fourth day. Then the food and fecal samples of all subjects were collected for 12 consecutive days. The total zinc and the stable zinc isotope ratio of all samples were determined by atomic absorption spectrophotometer and thermal ionization mass spectrometer, respectively. The determination of the other nutrients was performed based on the Chinese National Standard Methods. Among volunteers, the daily intake of zinc was 15.50 mg, 103.33 % of recommended nutrient intake (RNI, set by the Chinese Nutrition Society) in men and 15.43 mg, 134.17 % in women. The fractional absorption of Zn was 23.42 ± 2.23 % in men, and 22.49 ± 2.19 % in women. The protein candidates got from the typical diets was 93.96 % of RNI in women. Calcium and ascorbic acid intakes were 76.23 % of RNI and 27.91 % of RNI in men, respectively and 51.17 % of RNI and 34.23 % of RNI in women, respectively. Our results showed that a typical meal for someone in the Shandong rural region presented an adequate intake of zinc and a moderate Zn bioavailability. The shortage of protein and the inappropriate protein pattern may play important roles in reducing zinc bioavailability.

Discrimination of conventional and organic white cabbage from a long-term field trial study using untargeted LC-MS-based metabolomics

The influence of organic and conventional farming practices on the content of single nutrients in plants is disputed in the scientific literature. Here, large-scale untargeted LC-MS-based metabolomics was used to compare the composition of white cabbage from organic and conventional agriculture, measuring 1,600 compounds. Cabbage was sampled in 2 years from one conventional and two organic farming systems in a rigidly controlled long-term field trial in Denmark. Using Orthogonal Projection to Latent Structures–Discriminant Analysis (OPLS-DA), we found that the production system leaves a significant (p = 0.013) imprint in the white cabbage metabolome that is retained between production years. We externally validated this finding by predicting the production system of samples from one year using a classification model built on samples from the other year, with a correct classification in 83 % of cases. Thus, it was concluded that the investigated conventional and organic management practices have a systematic impact on the metabolome of white cabbage. This emphasizes the potential of untargeted metabolomics for authenticity testing of organic plant products.