The Choice Between Light, Dark, or Medium
Coffee has several superpowers, but they’re determined by how long the beans are roasted. Here’s how to choose the right one for your needs.
It wouldn’t be a revelation to say that coffee is a popular beverage for athletes and non-athletes alike. Humans have been consuming it at least since 1,000 AD. In the USA, it’s the number one source of caffeine consumption (1,2).
For those who don’t consume much in the way of fruits and vegetables, it’s also an important source of phytonutrients and has various potential health benefits, according to epidemiological studies (3,4).
The question remains, though: Does one roast (light, medium, or dark) have more healthful attributes than the others? Well, let’s find out.
The Roasting Process
When roasting coffee beans, the raw beans are subjected to heat for a specific amount of time, typically resulting in a change of color from the raw, green bean to a yellow and subsequent light brown color, which further darkens as the bean roasts. The higher the temperature and time of roasting, the darker the roast.
Light roast coffee is subjected to the least amount of heat. This result? More chlorogenic acids are retained in the finished coffee. These chlorogenic acids are responsible for some of the potential health benefits of coffee, including potential weight loss (5).
Dark roast coffee is subjected to the greatest amount of heat, which, unfortunately, results in the degradation and transformation of the chlorogenic acids. However, while dark roast coffee is much lower in chlorogenic acids, it’s rich in N-methylpyridinium, a degradation product of the trigonelline formed during roasting. While not touted as often as the chlorogenic acids, N-methylpyridinium-rich dark roast coffee also has some potential health benefits:
- A dark roast coffee blend reduced DNA damage in healthy men and women consuming 500 mL per day (about 4 cups) over 4 weeks (6). An 8-week study also found similar results in those consuming 750 mL/day (7).
- In pre-obese people consuming 500 mL of coffee a day for 4 weeks (8), a dark roast coffee increased weight loss while a light roast didn’t. (Normal-weight subjects consuming dark or light roast had no significant change.)
- Another study indicated potentially increased thermogenesis via uncoupling protein-2 (UCP-2) expression, which was increased in healthy, normal-weight men and women consuming 750 mL/day of dark-roast coffee over 4 weeks (10).
- There’s also evidence that dark roast caused reduced calorie intake, body weight, and body fat, along with a slight gain in fat-free mass in healthy men and women consuming 750 mL/day over 4 weeks (11). The decrease in body fat was greater to a statistically significant extent than a medium roast (11). A 24-week study also found a decrease in fat mass in those consuming 4 cups per day of a medium dark roast (20).
- Dark roast increased the antioxidative status of red blood cells to a greater extent than light roast coffee (8).
- Dark roast increased glucose metabolism to a greater degree than light roast in healthy men consuming 4 cups/day for 1 week (12).
- Dark roast inhibited phosphodiesterase or PDE in vitro to a greater degree than light roast at identical concentrations (13). PDE is the enzyme that breaks down cAMP – a second messenger involved in various processes, including lipolysis.
- In vitro data demonstrated potentially greater anti-inflammatory effects with dark roast coffee versus lighter roasts (14). There’s also evidence suggesting that dark roast may be easier on your stomach than light roast (15).
- In humans, dark roast coffee demonstrated a greater increase in the transcription factor (Nrf2) which is responsible for inducing the expression of antioxidant and cytoprotective/detoxifying enzymes that activate our own body’s naturally evolved defense mechanisms against chronic oxidative stress and xenobiotic harm (16-18). Activation of Nrf2 is at least partially responsible for the benefits of foods such as broccoli (19). However, some studies have found only a minimal influence of dark roast coffee on Nrf2 (7).
Let’s Go to the Scorecard
While these points may make it seem as though dark roast is the obvious choice, there are some limitations to note:
- While in vitro data found dark roast inhibited PDE to a greater extent than light roast, a human study that administered a dark and medium roast found little difference in PDE activity. Whether a light roast coffee would’ve been different is unknown, but there were substantial differences in the content of chlorogenic acids and N-methylpyridinium (10). (Caffeine itself can’t effectively inhibit PDE in humans at normal concentrations, so this is an interesting finding.)
- With the exception of a greater decrease in body fat, the decreases in body weight, calorie intake, and a slight increase in fat-free mass weren’t statistically different between a dark and medium roast (11). Both dark and medium roast demonstrated a decrease in body fat and a slight increase in fat-free mass (11). Additionally, increases in UCP-2 weren’t statistically different between a medium and dark roast, and the increase in the dark roast may have been confounded by time effects (10).
- While in vitro data demonstrated potentially greater antioxidative and anti-inflammatory effects with dark roast, other data generally show greater antioxidative and anti-inflammatory effects with light roast (21). In an animal model, the results were mixed (22).
- While dark roast increased UCP-2 expression in humans, a medium roast was able to increase the hormones adiponectin and leptin, while dark roast wasn’t. These hormones play a role in energy homeostasis and may have anti-obesity effects. It should be noted, only the effect upon leptin was statistically significant for medium versus dark roast (10).
- While one study found dark roast coffee increased glucose metabolism, another found that dark and light roasts are no different in terms of an effect on glucose or insulin levels (23).
- A study in overweight men and women consuming around 4-5 cups/day for 3 months experienced no difference in weight loss when comparing dark and medium roasts (24).
- Another study found effectively similar antioxidative effects in people consuming medium and dark roast coffee (25).
- Chlorogenic acid, a major constituent of light roast but not dark, has some evidence for causing a decrease in fat mass in overweight individuals (26).
A Comparison of Caffeine Levels
There are studies showing that both dark and light roasts may have more caffeine than the other, but more importantly, these differences aren’t substantial enough to base your choice on the potential amount of caffeine present (14,27-30). In other words, it’s a toss-up.
How About Acrylamide Levels?
Acrylamide and its presence in coffee made the news media rounds a few years ago because acrylamide is classified as a “probable” human carcinogen by the International Agency for Research on Cancer (IARC).
Acrylamide can be formed via the Maillard reaction, which requires the presence of an amino acid, a reducing sugar (e.g., glucose or fructose), and heat. This is the main mechanism through which it occurs, not only in coffee but many other foods, especially potatoes and baked goods (31,32).
Frying, baking, grilling, roasting, toasting, and microwaving carbohydrate-rich foods can generate acrylamide formation (31,32). Boiling or steaming is okay.
While vegetables and meat can form some acrylamide when subjected to these cooking methods, it’s generally much less than baked goods and potatoes (31-33). For coffee and other plant-based sources of acrylamide, the amino acid asparagine is considered the main contributor to acrylamide formation (34).
Despite rather significant consumption of acrylamide, epidemiological studies have largely failed to find any evidence of an increased risk of cancer from consumption of acrylamide from dietary sources (35-38). While risk assessments based largely upon animal model data have indicated concern for acrylamide consumption, intake from coffee alone probably isn’t something to be concerned about (38-42).
Consumption of acrylamide in coffee isn’t done in a vacuum and should certainly be considered distinct from the consumption of foods such as baked goods, fried potato chips, and other potato products, as well as tobacco smoking, which are significant sources (43).
Coffee, however, has antioxidant and anti-inflammatory effects which may mitigate the potentially harmful effects of acrylamide and its metabolite. Besides, the Maillard reaction that’s responsible for producing acrylamide in coffee is also responsible for producing at least some of the antioxidative and anti-inflammatory effects of coffee while also producing many of the smells and tastes of coffee that people covet (34,44,45).
Epidemiological studies have either failed to show an association between coffee consumption and cancer or have shown a reduced likelihood (46-51).
The bottom line? Coffee alone isn’t something to be too worried about with respect to acrylamide consumption. In fact, the IARC more recently concluded that coffee itself shouldn’t be considered “possibly carcinogenic” and that increased cancer risk from drinking coffee is specifically related to esophageal cancer and consumption of very hot liquids – tea, coffee, or even water. So, consider drinking your beverages, including coffee, at a reasonable temperature – below 150 degrees Fahrenheit – for risk reduction.
Nonetheless, if you want to reduce the amount of acrylamide in your coffee, opting for medium and dark roasts is best. The acrylamide is degraded/transformed as the roasting temperature and time rise, causing a substantial decrease in the amount of acrylamide present in medium and dark roasts relative to light roasts (52-54).
So, What’s the Best Coffee to Drink?
There isn’t enough evidence to suggest that you should only drink one roast versus another. As with most things in life, variety is ideal. If you normally drink only light roast, give medium or dark a try for a few weeks and vice versa. Ultimately, drink the coffee you enjoy the most.
- Fredholm BB. Notes on the history of caffeine use. Dalam: Fredholm, BB. Methylxanthines, Handbook of Experimental Pharmacology. 2011:1-9.
- Verster JC, Koenig J. Caffeine intake and its sources: A review of national representative studies. Critical reviews in food science and nutrition. 2018 May 24;58(8):1250-9.
- Gunter MJ, Murphy N, Cross AJ, et al. Coffee drinking and mortality in 10 European countries: a multinational cohort study. Annals of internal medicine. 2017 Aug 15;167(4):236-47.
- Saeed M, Naveed M, BiBi J, et al. Potential nutraceutical and food additive properties and risks of coffee: a comprehensive overview. Critical reviews in food science and nutrition. 2019 Nov 13;59(20):3293-319.
- Tajik N, Tajik M, Mack I, et al. The potential effects of chlorogenic acid, the main phenolic components in coffee, on health: a comprehensive review of the literature. European journal of nutrition. 2017 Oct 1;56(7):2215-44.
- Schipp D, Tulinska J, Sustrova M, et al. Consumption of a dark roast coffee blend reduces DNA damage in humans: results from a 4-week randomised controlled study. European journal of nutrition. 2019 Dec 1;58(8):3199-206.
- Pahlke G, Attakpah E, Aichinger G, et al. Dark coffee consumption protects human blood cells from spontaneous DNA damage. Journal of functional foods. 2019 Apr 1;55:285-95.
- Kotyczka C, Boettler U, Lang R, et al. Dark roast coffee is more effective than light roast coffee in reducing body weight, and in restoring red blood cell vitamin E and glutathione concentrations in healthy volunteers. Molecular nutrition & food research. 2011 Oct;55(10):1582-6.
- Riedel A, Hochkogler CM, Lang R, et al. N-Methylpyridinium, a degradation product of trigonelline upon coffee roasting, stimulates respiratory activity and promotes glucose utilization in HepG2 cells. Food & function. 2014;5(3):454-62.
- Riedel A, Dieminger N, Bakuradze T, Lang R, Parra GA, Hochkogler CM, Winkler S, Bytof G, Lantz I, Stiebitz H, Richling E. A 4-week consumption of medium roast and dark roast coffees affects parameters of energy status in healthy subjects. Food research international. 2014 Sep 1;63:409-19.
- Bakuradze T, Parra GA, Riedel A, Somoza V, Lang R, Dieminger N, Hofmann T, Winkler S, Hassmann U, Marko D, Schipp D. Four-week coffee consumption affects energy intake, satiety regulation, body fat, and protects DNA integrity. Food Research International. 2014 Sep 1;63:420-7.
- Di Girolamo FG, Mazzucco S, Situlin R, et al. Roasting intensity of naturally low-caffeine Laurina coffee modulates glucose metabolism and redox balance in humans. Nutrition. 2016 Sep 1;32(9):928-36.
- Montoya GA, Bakuradze T, Eirich M, et al. Modulation of 3′, 5′-cyclic AMP homeostasis in human platelets by coffee and individual coffee constituents. British journal of nutrition. 2014 Nov;112(9):1427-37.
- Paur I, Balstad TR, Blomhoff R. Degree of roasting is the main determinant of the effects of coffee on NF-κB and EpRE. Free Radical Biology and Medicine. 2010 May 1;48(9):1218-27.
- Rubach M, Lang R, Bytof G, et al. A dark brown roast coffee blend is less effective at stimulating gastric acid secretion in healthy volunteers compared to a medium roast market blend. Molecular nutrition & food research. 2014 Jun;58(6):1370-3.
- Boettler U, Volz N, Pahlke G, et al. Coffees rich in chlorogenic acid or N‐methylpyridinium induce chemopreventive phase II‐enzymes via the Nrf2/ARE pathway in vitro and in vivo. Molecular nutrition & food research. 2011 May;55(5):798-802.
- Vomund S, Schäfer A, Parnham MJ, et al. Nrf2, the master regulator of antioxidative responses. International journal of molecular sciences. 2017 Dec;18(12):2772.
- Bocci V, Valacchi G. Nrf2 activation as target to implement therapeutic treatments. Frontiers in chemistry. 2015 Feb 2;3:4.
- Dinkova-Kostova AT, Fahey JW, Kostov RV, et al. KEAP1 and done? Targeting the NRF2 pathway with sulforaphane. Trends in food science & technology. 2017 Nov 1;69:257-69.
- Alperet DJ, Rebello SA, Khoo EY, et al. The effect of coffee consumption on insulin sensitivity and other biological risk factors for type 2 diabetes: a randomized placebo-controlled trial. The American Journal of Clinical Nutrition. 2020.
- Jung S, Kim MH, Park JH, et al. Cellular antioxidant and anti-inflammatory effects of coffee extracts with different roasting levels. Journal of medicinal food. 2017 Jun 1;20(6):626-35.
- Choi S, Jung S, Ko KS. Effects of coffee extracts with different roasting degrees on antioxidant and anti-inflammatory systems in mice. Nutrients. 2018 Mar;10(3):363.
- Rakvaag E, Dragsted LO. Acute effects of light and dark roasted coffee on glucose tolerance: a randomized, controlled crossover trial in healthy volunteers. European journal of nutrition. 2016 Oct 1;55(7):2221-30.
- Kempf K, Kolb H, Gärtner B, et al. Cardiometabolic effects of two coffee blends differing in content for major constituents in overweight adults: a randomized controlled trial. European journal of nutrition. 2015 Aug 1;54(5):845-54.
- Corrêa TA, Monteiro MP, Mendes TM, et al. Medium light and medium roast paper-filtered coffee increased antioxidant capacity in healthy volunteers: results of a randomized trial. Plant foods for human nutrition. 2012 Sep 1;67(3):277-82.
- Watanabe T, Kobayashi S, Yamaguchi T, et al. Coffee Abundant in Chlorogenic Acids Reduces Abdominal Fat in Overweight Adults: A Randomized, Double-Blind, Controlled Trial. Nutrients. 2019 Jul;11(7):1617.
- Ludwig IA, Mena P, Calani L, et al. Variations in caffeine and chlorogenic acid contents of coffees: what are we drinking?. Food & function. 2014;5(8):1718-26.
- Hečimović I, Belščak-Cvitanović A, Horžić D, et al. Comparative study of polyphenols and caffeine in different coffee varieties affected by the degree of roasting. Food chemistry. 2011 Dec 1;129(3):991-1000.
- Tfouni SA, Carreiro LB, Teles CR, et al. Caffeine and chlorogenic acids intake from coffee brew: influence of roasting degree and brewing procedure. International journal of food science & technology. 2014 Mar;49(3):747-52.
- Tfouni SA, Serrate CS, Carreiro LB, et al. Effect of roasting on chlorogenic acids, caffeine and polycyclic aromatic hydrocarbons levels in two Coffea cultivars: Coffea arabica cv. Catuaí Amarelo IAC‐62 and Coffea canephora cv. Apoatã IAC‐2258. International journal of food science & technology. 2012 Feb;47(2):406-15.
- Keramat J, LeBail A, Prost C, et al. Acrylamide in foods: chemistry and analysis. A review. Food and bioprocess technology. 2011 Apr 1;4(3):340-63.
- Rydberg P, Eriksson S, Tareke E, et al. Factors that influence the acrylamide content of heated foods. In Chemistry and safety of acrylamide in food 2005 (pp. 317-328). Springer, Boston, MA.
- Pacetti D, Gil E, Frega NG, et al. Acrylamide levels in selected Colombian foods. Food Additives & Contaminants: Part B. 2015 Apr 3;8(2):99-105.
- Guenther H, Anklam E, Wenzl T, et al. Acrylamide in coffee: review of progress in analysis, formation and level reduction. Food Additives and Contaminants. 2007 Jul 1;24(sup1):60-70.
- Pelucchi C, Bosetti C, Galeone C, et al. Dietary acrylamide and cancer risk: an updated meta‐analysis. International journal of cancer. 2015 Jun 15;136(12):2912-22.
- Pelucchi C, La Vecchia C, Bosetti C, et al. Exposure to acrylamide and human cancer—a review and meta-analysis of epidemiologic studies. Annals of Oncology. 2011 Jul 1;22(7):1487-99.
- Graff RE, Cho E, Preston MA, et al. Dietary acrylamide intake and risk of renal cell carcinoma in two large prospective cohorts. Cancer Epidemiology and Prevention Biomarkers. 2018 Aug 1;27(8):979-82.
- EFSA Panel on Contaminants in the Food Chain (CONTAM). Scientific Opinion on acrylamide in food. EFSA Journal. 2015 Jun;13(6):4104.
- Parzefall W. Minireview on the toxicity of dietary acrylamide. Food and Chemical Toxicology. 2008 Apr 1;46(4):1360-4.
- Outzen M, Egeberg R, Dragsted L, et al. Dietary determinants for Hb-acrylamide and Hb-glycidamide adducts in Danish non-smoking women. British journal of nutrition. 2011 May;105(9):1381-7.
- Kopp EK, Dekant W. Toxicokinetics of acrylamide in rats and humans following single oral administration of low doses. Toxicology and applied pharmacology. 2009 Mar 1;235(2):135-42.
- Li D, Wang P, Liu Y, et al. Metabolism of acrylamide: interindividual and interspecies differences as well as the application as biomarkers. Current drug metabolism. 2016 May 1;17(4):317-26.
- Lipworth L, Sonderman JS, Tarone RE, et al. Acrylamide: a human cancer risk?. European Journal of Cancer Prevention. 2013 Mar 1;22(2):193-4.
- Liu Y, Kitts DD. Confirmation that the Maillard reaction is the principle contributor to the antioxidant capacity of coffee brews. Food Research International. 2011 Oct 1;44(8):2418-24.
- Mottram DS. The Maillard reaction: source of flavour in thermally processed foods. In Flavours and fragrances 2007 (pp. 269-283). Springer, Berlin, Heidelberg.
- Ong JS, Law MH, An J, et al. Association between coffee consumption and overall risk of being diagnosed with or dying from cancer among> 300 000 UK Biobank participants in a large-scale Mendelian randomization study. International journal of epidemiology. 2019 Oct 1;48(5):1447-56.
- Loftfield E, Cornelis MC, Caporaso N, et al. Association of coffee drinking with mortality by genetic variation in caffeine metabolism: findings from the UK Biobank. JAMA internal medicine. 2018 Aug 1;178(8):1086-97.
- Kim Y, Je Y, Giovannucci E. Coffee consumption and all-cause and cause-specific mortality: a meta-analysis by potential modifiers.
- Sado J, Kitamura T, Kitamura Y, et al. Association between coffee consumption and all‐sites cancer incidence and mortality. Cancer science. 2017 Oct;108(10):2079-87.
- Grosso G, Micek A, Godos J, et al. Coffee consumption and risk of all-cause, cardiovascular, and cancer mortality in smokers and non-smokers: a dose-response meta-analysis. Eur J Epidemiol 2016 31, 1191–1205.
- Crippa A, Discacciati A, Larsson SC, et al. Coffee consumption and mortality from all causes, cardiovascular disease, and cancer: a dose-response meta-analysis. American journal of epidemiology. 2014 Oct 15;180(8):763-75.
- Summa CA, de la Calle B, Brohee M, et al. Impact of the roasting degree of coffee on the in vitro radical scavenging capacity and content of acrylamide. LWT-Food Science and Technology. 2007 Dec 1;40(10):1849-54.
- Lantz I, Ternité R, Wilkens J, et al. Studies on acrylamide levels in roasting, storage and brewing of coffee. Molecular nutrition & food research. 2006 Nov;50(11):1039-46.
- Alves RC, Soares C, Casal S, et al. Acrylamide in espresso coffee: Influence of species, roast degree and brew length. Food Chemistry. 2010 Apr 1;119(3):929-34.