SCIENCE  |  NUTRITION

Coffee

Coffee contains several bioactive compounds that contribute to its health benefits. Key chemicals include chlorogenic acids, a type of polyphenol that acts as a powerful antioxidant, reducing inflammation and protecting against chronic diseases. Additionally, caffeine enhances cognitive function and mood, while diterpenes like cafestol and kahweol support liver health and have anti-inflammatory properties.

coffee

Coffee consumption has been extensively studied for its potential health benefits. The compiled research suggests several positive impacts on health:

Cardiovascular Health:

General Cardiovascular Benefits: Coffee consumption is associated with lower risks of cardiovascular disease and mortality. Regular coffee drinkers tend to have a reduced risk of cardiovascular conditions, potentially due to coffee’s anti-inflammatory and antioxidant properties (Int J Epidemiol. 2022, Am J Clin Nutr. 2022).

Homocysteine Levels: Coffee supplementation significantly increases homocysteine levels, a marker associated with cardiovascular risk. Despite this increase, the overall cardiovascular benefits of coffee may outweigh the potential risks related to elevated homocysteine, suggesting that the relationship between coffee consumption and cardiovascular health is complex and warrants further investigation (Curr Pharm Des. 2023).

Cancer Prevention:

Endometrial Cancer: Coffee consumption is inversely associated with the risk of endometrial cancer. Higher coffee intake correlates with a lower risk of developing this type of cancer, especially among individuals with higher BMI. The presence of antioxidants and other chemopreventive compounds in coffee may contribute to these protective effects (Am J Clin Nutr. 2022).

General Cancer Risk: Regular coffee intake is linked to a probable decreased risk of several cancers, including breast, colorectal, colon, endometrial, and prostate cancers (Annu Rev Nutr. 2017, Int J Epidemiol. 2022).

Metabolic Health:

Type 2 Diabetes: Coffee consumption is inversely related to the risk of developing type 2 diabetes. Each additional cup of coffee per day is associated with a reduced risk, suggesting that coffee’s thermogenic, antioxidative, and anti-inflammatory effects may help prevent diabetes (Nutr Rev. 2018, Annu Rev Nutr. 2017).

Blood Glucose Levels: Green coffee bean extract (GCBE) supplementation can significantly alter fasting blood sugar levels, particularly when consumed in higher doses (≥400 mg/day). This indicates potential benefits for managing blood glucose and insulin levels (Phytother Res. 2020).

Liver Health:

Liver Function and Inflammation: GCBE supplementation may enhance antioxidant capacity and reduce inflammatory markers like TNF-α, which is beneficial for liver health and may lower the risk of non-alcoholic fatty liver disease (NAFLD) and other chronic diseases (Complement Ther Clin Pract. 2021).

Kidney Health:

Chronic Kidney Disease (CKD): Coffee intake is associated with a lower risk of CKD, end-stage kidney disease (ESKD), and albuminuria. Regular consumption of coffee can potentially reduce the incidence and progression of CKD-related outcomes (J Ren Nutr. 2021).

Longevity and Mortality:

General Mortality: Coffee consumption is linked to a lower risk of death from all causes, including cardiovascular disease and cancer. The protective effects are more pronounced in populations consuming higher amounts of coffee daily (Int J Epidemiol. 2022, Am J Clin Nutr. 2022).

Antioxidant and Polyphenolic Benefits:

Polyphenols and Antioxidants: Coffee, especially when lightly or medium roasted, is rich in polyphenols and antioxidants. These compounds contribute to coffee’s health benefits by reducing oxidative stress and inflammation (J Environ Sci Health B. 2020, Food Chem. 2011, Rocz Panstw Zakl Hig. 2017).

Overall, the evidence indicates that moderate coffee consumption can be part of a healthy diet, offering various protective effects against chronic diseases, improving metabolic health, and potentially contributing to longevity.

Best Variety of Coffee and Roast for Health Benefits

The health benefits of coffee are influenced significantly by both the variety of coffee and the degree of roasting. Here’s a detailed look into the findings:

VARIETY OF COFFEE:

Arabica Coffee: Generally, Arabica coffee beans are noted for their higher polyphenolic content compared to Robusta varieties. The study on Arabica green coffee beans highlights the presence of various polyphenols and methylxanthines, contributing to a high antioxidant capacity (J Agric Food Chem. 2016).

Green Coffee: Green coffee beans, particularly Arabica, contain a rich profile of bioactive compounds, including chlorogenic acids, which have significant antioxidant properties (J Agric Food Chem. 2016). These compounds are known to contribute to various health benefits such as improved cardiovascular health and reduced risk of chronic diseases.

DEGREE OF ROASTING:

Light Roasting: Lightly roasted coffee tends to retain more polyphenols and exhibits higher antioxidant capacity compared to medium and dark roasts. Studies indicate that the total polyphenolic content is highest in light roasted coffees, contributing significantly to their antioxidant properties (J Environ Sci Health B. 2020).

Medium Roasting: While medium roasting slightly reduces the polyphenolic content compared to light roasting, it still maintains a substantial amount of these beneficial compounds. This degree of roasting balances the retention of bioactive compounds and the development of favorable flavor profiles (Rocz Panstw Zakl Hig. 2017).

Dark Roasting: Dark roasted coffees show a significant decline in polyphenols but an increase in antioxidant activity due to the formation of Maillard-reaction products. Despite the reduction in natural antioxidants, the Maillard products compensate by enhancing the total antioxidant capacity (J Environ Sci Health B. 2020).

CONCLUSION:

For optimal health benefits, lightly roasted Arabica coffee appears to be the best choice. This variety and roast level preserve the highest levels of polyphenols and maintain a strong antioxidant capacity, contributing to various health benefits such as improved cardiovascular health, reduced risk of chronic diseases, and overall enhanced metabolic health.

PUBLICATIONS

  1. Effects of Coffee Supplementation on Homocysteine and Leptin Levels: A Systematic Review and Meta-analysis of Clinical Trials.
          • Curr Pharm Des. 2023;29(1):30-36.
          • Design: Meta-analysis of clinical trials.
          • Summary: Coffee administration significantly increases homocysteine levels but has no significant changes in leptin concentrations.
  2. Coffee consumption and risk of endometrial cancer: a pooled analysis of individual participant data in the Epidemiology of Endometrial Cancer Consortium (E2C2).
          • Am J Clin Nutr. 2022 Nov;116(5):1219-1228.
          • Design: Pooled analysis of epidemiologic studies.
          • Summary: Coffee drinkers had a lower risk of endometrial cancer, with a dose-response relation between higher coffee consumption and lower risk.
  3. Coffee and tea consumption and mortality from all causes, cardiovascular disease and cancer: a pooled analysis of prospective studies from the Asia Cohort Consortium.
          • Int J Epidemiol. 2022 May 9;51(2):626-640.
          • Design: Pooled analysis of prospective cohort studies.
          • Summary: Coffee consumption is associated with a lower risk of death overall and with lower risks of death from cardiovascular disease and cancer. Green tea consumption is associated with lower risks of death from all causes and cardiovascular disease.
  4. Effect of green coffee bean extract supplementation on liver function and inflammatory biomarkers: A meta-analysis of randomized clinical trials.
          • Complement Ther Clin Pract. 2021 May;43:101349.
          • Design: Meta-analysis of randomized clinical trials.
          • Summary: Green coffee bean extract supplementation attenuated TNF-α, a circulating inflammatory marker mediator which may be linked with lower systemic inflammation.
  5. The Effect of Green Coffee Bean Extract on Cardiovascular Risk Factors: A Systematic Review and Meta-analysis.
          • Adv Exp Med Biol. 2021;1328:323-345.
          • Design: Systematic review and meta-analysis.
          • Summary: Green coffee bean extract consumption can improve total cholesterol, triglycerides, body weight, blood pressure, and fasting plasma glucose.
  6. Effect of Coffee Consumption on Renal Outcome: A Systematic Review and Meta-Analysis of Clinical Studies.
          • J Ren Nutr. 2021 Jan;31(1):5-20.
          • Design: Systematic review and meta-analysis.
          • Summary: Coffee intake was dose-dependently associated with lower incident chronic kidney disease (CKD), end-stage kidney disease (ESKD), and albuminuria.
  7. The influence of green coffee bean extract supplementation on blood glucose levels: A systematic review and dose-response meta-analysis of randomized controlled trials.
          • Phytother Res. 2020 Sep;34(9):2159-2169.
          • Design: Systematic review and dose-response meta-analysis of randomized controlled trials.
          • Summary: Green coffee extract (GCE) consumption significantly alters fasting blood sugar (FBS) levels, with significant improvements in insulin levels when GCE is supplemented in doses ≥400 mg/day.
  8. The effect of roasting on the total polyphenols and antioxidant activity of coffee.
          • J Environ Sci Health B. 2020;55(5):495-500.
          • Design: Analysis of ground beans of green, light, medium, and dark roasted coffee.
          • Summary: Roasting process affects both the oxidative activity as well as polyphenolic content, with light roasted coffees showing the highest polyphenol content and antioxidant capacity.
  9. Coffee consumption and reduced risk of developing type 2 diabetes: a systematic review with meta-analysis.
          • Nutr Rev. 2018 Jun 1;76(6):395-417.
          • Design: Systematic review and meta-analysis of 30 prospective studies.
          • Summary: Coffee consumption is inversely associated with the risk of developing type 2 diabetes, with possible mechanisms including thermogenic, antioxidative, and anti-inflammatory effects.
  10. Coffee, Caffeine, and Health Outcomes: An Umbrella Review.
          • Annu Rev Nutr. 2017 Aug 21;37:131-156.
          • Design: Umbrella review of meta-analyses of observational studies and randomized controlled trials.
          • Summary: Coffee consumption is associated with a probable decreased risk of several cancers, cardiovascular disease, mortality, Parkinson’s disease, and type-2 diabetes. Caffeine is associated with a probable decreased risk of Parkinson’s disease and type-2 diabetes but an increased risk of pregnancy loss.
  11. Assessing polyphenols content and antioxidant activity in coffee beans according to origin and the degree of roasting.
          • Rocz Panstw Zakl Hig. 2017;68(4):347-353.
          • Design: Study on natural coffee beans (100% Arabica) from different regions and their polyphenol content and antioxidant activity.
          • Summary: Polyphenol levels and antioxidant activities depend on the coffee’s origin and degree of roasting, with lighter roasts having higher polyphenol content and antioxidant activities.
  12. Exhaustive Qualitative LC-DAD-MS(n) Analysis of Arabica Green Coffee Beans: Cinnamoyl-glycosides and Cinnamoylshikimic Acids as New Polyphenols in Green Coffee.
          • J Agric Food Chem. 2016 Dec 28;64(51):9663-9674.
          • Design: Analysis of four Arabica green coffee beans from different geographical origins.
          • Summary: Green coffee represents an important source of polyphenols and methylxanthines, with high antioxidant capacity. African coffees showed higher polyphenolic content than American beans.
  13. Polyphenolic and hydroxycinnamate contents of whole coffee fruits from China, India, and Mexico.
          • J Agric Food Chem. 2013 Jun 5;61(22):5298-309.
          • Design: Analysis of air-dried whole coffee fruits, beans, and husks from China, India, and Mexico.
          • Summary: The CGA content was similar for both Mexican and Indian coffee fruits but was much lower in the samples from China. Both phenols and methylxanthines contributed to the antioxidant capacity associated with green coffee.
  14. Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting.
          • Food Chem. 2011 Dec 1;129(3):991-1000.
          • Design: Study on the bioactive composition of four different coffee varieties.
          • Summary: The highest content of total and individual polyphenolic compounds was determined in coffees roasted in both light and medium roasting conditions. The highest caffeine content was found in light roasted Cherry coffee.
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