Consumption of a dark roast coffee blend reduces DNA damage in humans: results from a 4-week randomised controlled study

Impact of coffee and its bioactive compounds on the risks of type 2 diabetes and its complications: A comprehensive review

BACKGROUND

Coffee beans have a long history of use as traditional medicine by various indigenous people. Recent focus has been given to the health benefits of coffee beans and its bioactive compounds. Research on the bioactivities, applications, and effects of processing methods on coffee beans' phytochemical composition and activities has been conducted extensively. The current review attempts to provide an update on the biological effects of coffee on type 2 diabetes (T2D) and its comorbidities.

METHODS

Comprehensive literature search was carried out on peer-reviewed published data on biological activities of coffee on in vitro, in vivo and epidemiological research results published from January 2015 to December 2022, using online databases such as PubMed, Google Scholar and ScienceDirect for our searches.

RESULTS

The main findings were: firstly, coffee may contribute to the prevention of oxidative stress and T2D-related illnesses such as cardiovascular disease, retinopathy, obesity, and metabolic syndrome; secondly, consuming up to 400 mg/day (1-4 cups per day) of coffee is associated with lower risks of T2D; thirdly, caffeine consumed between 0.5 and 4 h before a meal may inhibit acute metabolic rate; and finally, both caffeinated and decaffeinated coffee are associated with reducing the risks of T2D.

CONCLUSION

Available evidence indicates that long-term consumption of coffee is associated with decreased risk of T2D and its complications as well as decreased body weight. This has been attributed to the consumption of coffee with the abundance of bioactive chemicals.

Use of the Single Cell Gel Electrophoresis Assay for the Detection of DNA-protective Dietary Factors: Results of Human Intervention Studies

The single cell gel electrophoresis technique is based on the measurement of DNA migration in an electric field and enables to investigate via determination of DNA-damage the impact of foods and their constituents on the genetic stability. DNA-damage leads to adverse effects including cancer, neurodegenerative disorders and infertility. In the last 25 years approximately 90 human intervention trials have been published in which DNA-damage, formation of oxidized bases, alterations of the sensitivity towards reactive oxygen species and chemicals and of repair functions were investigated with this technique. In approximately 50% of the studies protective effects were observed. Pronounced protection was found with certain plant foods (spinach, kiwi fruits, onions), coffee, green tea, honey and olive oil. Also diets with increased contents of vegetables caused positive effects. Small amounts of certain phenolics (gallic acid, xanthohumol) prevented oxidative damage of DNA; with antioxidant vitamins and cholecalciferol protective effects were only detected after intake of doses that exceed the recommended daily uptake values. The evaluation of the quality of the studies showed that many have methodological shortcomings (lack of controls, no calibration of repair enzymes, inadequate control of the compliance and statistical analyses) which should be avoided in future investigations.

No Association Observed Between Coffee Intake and Risk of Non-Hodgkin's Lymphoma among Postmenopausal Women

BACKGROUND

Some preliminary studies indicate that components in coffee may have anticarcinogenic effects. However, the association between coffee-drinking habits and the risk of NHL remain controversial.

OBJECTIVE

To examine the relationship between coffee intake and non-Hodgkin's lymphoma (NHL) incidence in a large prospective study of postmenopausal US women.

DESIGN AND PARTICIPANTS/SETTING

The participants included 74,935 women from the Women's Health Initiative Observational Study (WHI-OS) who were recruited from 1993 through 1998. Information about coffee-drinking habits was collected at baseline via self-administered questionnaires.

MAIN OUTCOME MEASURES

Newly diagnosed NHL was validated by medical records and pathology records. Separate analyses were performed for the following three subtypes of NHL: diffuse large B-cell lymphoma (DLBCL (n=244)), follicular lymphoma (FL (n=166)), and chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL (n=64)).

STATISTICAL ANALYSES PERFORMED

Age-adjusted and multivariable-adjusted Cox proportional hazards models were used to determine associations of coffee intake (specifically, the total amount of coffee consumed daily, coffee types, and coffee preparation methods) with risk of NHL.

RESULTS

A total of 851 women developed NHL during a median 18.34 years of follow-up (range, 0.01 to 24.30 years; SD ± 6.63 years). Overall, no associations were observed between coffee intake and risk of NHL regardless of the total amount of daily coffee intake (P-value for trend test = 0.90), caffeinated (P-value=0.55) or decaffeinated coffee intake (P-value=0.78), and filtered or unfiltered coffee intake (P-value=0.91) after controlling for sociodemographic factors, lifestyle risk factors, and clinical risk factors/current medical conditions. No significant associations were observed between coffee intake with specific subtypes of NHL. A statistically significant interaction was found between alcohol intake, coffee intake, and incident NHL (P-value for interaction=0.02) based on the adjusted analysis. Specifically, among women who frequently consumed alcohol (>7 drinks/week), those who had moderate coffee intake (2-3 cups coffee/day) had a significantly reduced risk of developing NHL (HR:0.61, 95%CI: 0.36-0.98), compared to those who did not drink coffee.

CONCLUSION

The findings from this study do not support an association between coffee consumption and NHL risk, irrespective of the total amount of daily coffee intake, coffee types, or coffee preparation methods.

Effect of Coffee and Cocoa-Based Confectionery Containing Coffee on Markers of DNA Damage and Lipid Peroxidation Products: Results from a Human Intervention Study

The effect of coffee and cocoa on oxidative damage to macromolecules has been investigated in several studies, often with controversial results. This study aimed to investigate the effect of one-month consumption of different doses of coffee or cocoa-based products containing coffee on markers of DNA damage and lipid peroxidation in young healthy volunteers. Twenty-one volunteers were randomly assigned into a three-arm, crossover, randomized trial. Subjects were assigned to consume one of the three following treatments: one cup of espresso coffee/day (1C), three cups of espresso coffee/day (3C), and one cup of espresso coffee plus two cocoa-based products containing coffee (PC) twice per day for 1 month. At the end of each treatment, blood samples were collected for the analysis of endogenous and H2O2-induced DNA damage and DNA oxidation catabolites, while urines were used for the analysis of oxylipins. On the whole, four DNA catabolites (cyclic guanosine monophosphate (cGMP), 8-OH-2'-deoxy-guanosine, 8-OH-guanine, and 8-NO2-cGMP) were detected in plasma samples following the one-month intervention. No significant modulation of DNA and lipid damage markers was documented among groups, apart from an effect of time for DNA strand breaks and some markers of lipid peroxidation. In conclusion, the consumption of coffee and cocoa-based confectionery containing coffee was apparently not able to affect oxidative stress markers. More studies are encouraged to better explain the findings obtained and to understand the impact of different dosages of these products on specific target groups.

DNA Protection by an Aronia Juice-Based Food Supplement

BACKGROUND

This study investigated the effects of an aronia juice-based food supplement on background and total DNA strand breaks in whole blood, and on H₂O₂-induced DNA strand breaks in isolated peripheral blood lymphocytes.

METHODS

Ninety-one healthy volunteers were randomly selected to consume either the food supplement (2 × 25 mL drinking ampules, n = 45) or no supplement (n = 46) daily for eight weeks.

RESULTS

Background DNA strand breaks decreased significantly after four and eight weeks of supplement consumption, compared to baseline (p < 0.05), but the overall effect was low, and neither group showed a decrease in total DNA strand breaks. Conversely, supplement consumption clearly reduced H₂O₂-induced DNA strand breaks ex vivo (p < 0.001), with statistically significant reductions after four and eight weeks, compared to the control group (p < 0.05).

CONCLUSIONS

Thus, although consuming antioxidant supplements might produce only marginal immediate benefits under healthy conditions, potential preventive effects warrant further investigation.

Health Effects of Coffee: Mechanism Unraveled?

The association of habitual coffee consumption with a lower risk of diseases, like type 2 diabetes mellitus, chronic liver disease, certain cancer types, or with reduced all-cause mortality, has been confirmed in prospective cohort studies in many regions of the world. The molecular mechanism is still unresolved. The radical-scavenging and anti-inflammatory activity of coffee constituents is too weak to account for such effects. We argue here that coffee as a plant food has similar beneficial properties to many vegetables and fruits. Recent studies have identified a health promoting mechanism common to coffee, vegetables and fruits, i.e., the activation of an adaptive cellular response characterized by the upregulation of proteins involved in cell protection, notably antioxidant, detoxifying and repair enzymes. Key to this response is the activation of the Nrf2 (Nuclear factor erythroid 2-related factor-2) system by phenolic phytochemicals, which induces the expression of cell defense genes. Coffee plays a dominant role in that regard because it is the major dietary source of phenolic acids and polyphenols in the developed world. A possible supportive action may be the modulation of the gut microbiota by non-digested prebiotic constituents of coffee, but the available data are still scarce. We conclude that coffee employs similar pathways of promoting health as assumed for other vegetables and fruits. Coffee beans may be viewed as healthy vegetable food and a main supplier of dietary phenolic phytochemicals.

DNA-BINDING and DNA-protecting activities of small natural organic molecules and food extracts

The review summarizes literature data on the DNA-binding, DNA-protecting and DNA-damaging activities of a range of natural human endogenous and exogenous compounds. Small natural organic molecules bind DNA in a site-specific mode, by arranging tight touch with the structure of the major and minor grooves, as well as individual bases in the local duplex DNA. Polyphenols are the best-studied exogenous compounds from this point of view. Many of them demonstrate hormetic effects, producing both beneficial and damaging effects. An attempt to establish the dependence of DNA damage or DNA protection on the concentration of the compound turned out to be successful for some polyphenols, daidzein, genistein and resveratrol, which were DNA protecting in low concentrations and DNA damaging in high concentrations. There was no evident dependence on concentration for quercetin and kaempferol. Probably, the DNA-protecting effect is associated with the affinity to DNA. Caffeine and theophylline are DNA binders; at the same time, they favor DNA repair. Although most alkaloids damage DNA, berberine can protect DNA against damage. Among the endogenous compounds, hormones belonging to the amine class, thyroid and steroid hormones appear to bind DNA and produce some DNA damage. Thus, natural compounds continue to reveal beneficial or adverse effects on genome integrity and provide a promising source of therapeutic activities.

Coffee C21 and protection of DNA from strand breaks: evaluation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006

Following an application from Tchibo GmbH submitted for authorisation of a health claim pursuant to Article 13(5) of Regulation (EC) No 1924/2006 via the Competent Authority of Germany, the EFSA Panel on Nutrition, Novel Foods and Food Allergens (NDA) was asked to deliver an opinion on the scientific substantiation of a health claim related to Coffee C21 and protection of DNA from strand breaks. The scope of the application was proposed to fall under a health claim based on newly developed scientific evidence. The food proposed by the applicant as the subject of the health claim is Coffee C21. The Panel considers that Coffee C21, a coffee standardised by its concentration of caffeoylquinic acids (CQA), trigonelline and N-methylpyridinium (NMP), is sufficiently characterised in relation to the claimed effect. The Panel considers that the claimed effect, protection of DNA from strand breaks, is a beneficial physiological effect. Out of the two human intervention studies from which conclusion could be drawn, one study provides some evidence that daily consumption of Coffee C21 (750 mL/day) for 4 weeks decreases DNA strand breaks in habitual coffee drinkers after coffee withdrawal over the previous four weeks. However, the results of this study were not replicated in another study conducted under similar conditions in the same study centre. No studies performed in a different setting, from which conclusions could be drawn, were available. No evidence has been provided for a mechanism by which coffee (including Coffee C21) would reduce DNA damage in human cells by reducing DNA strand breaks. The Panel concludes that a cause and effect relationship has not been established between the consumption of Coffee C21 and protection of DNA from strand breaks.