Tag: coffee study

Chinese Study: Sweetened Coffee Linked to Lower Risk of Early Death

Posted on by Qahwa World

Source: American College of Physicians / Annals of Internal Medicine |
Date: June 3, 2026

Chinese Study: Sweetened Coffee Linked to Lower Risk of Early Death

Key Findings:

  • Study from Southern Medical University in Guangzhou tracked over 171,000 people for 7 years.
  • Unsweetened coffee reduced death risk by 16 to 21 percent.
  • Coffee sweetened with one teaspoon of sugar per cup reduced risk by 29 to 31 percent.
  • Results for artificial sweeteners were inconclusive.
  • The study is observational, not experimental. It does not prove direct cause and effect.
  • Warning: Ready-made coffee drinks from chains contain much higher amounts of sugar.

Researchers from Southern Medical University in Guangzhou, China, published a new study in the journal Annals of Internal Medicine. The study examined the effect of sweetened coffee on the risk of early death. It included more than 171,000 participants from the UK Biobank project. The average follow-up period was about seven years.

As a result, the study found that drinking moderate amounts of coffee, whether sweetened or unsweetened, is associated with a lower risk of death. This research is one of the first large-scale studies to directly compare the effect of adding sugar to coffee on long-term health outcomes.

Key Results: Up to 31 Percent Lower Death Risk

The researchers divided participants into groups based on their coffee consumption. These groups included non-drinkers, unsweetened coffee drinkers, sugar-sweetened coffee drinkers, and artificially sweetened coffee drinkers. After seven years of follow-up, the results were clear.

First, people who drank any amount of unsweetened coffee were 16 to 21 percent less likely to die compared to non-drinkers. Second, those who drank 1.5 to 3.5 cups per day of sugar-sweetened coffee were 29 to 31 percent less likely to die. The researchers noted that these participants added only about one teaspoon of sugar (approximately 4 grams) per cup on average.

In contrast, the results for those who used artificial sweeteners were inconclusive. The reduced risk applied to deaths from cancer and cardiovascular disease as well.

Summary of Results

Coffee Type Daily Amount Reduction in Death Risk
Unsweetened coffee Any amount 16% to 21%
Sugar-sweetened coffee (1 tsp per cup) 1.5 to 3.5 cups 29% to 31%
Coffee with artificial sweeteners Varies Inconclusive

Why Is Coffee Beneficial? Possible Mechanisms

Coffee contains biologically active compounds that offer potential health benefits. The most important are antioxidants and polyphenols, especially chlorogenic acids. These compounds fight oxidative stress and inflammation. They also improve blood vessel function and glucose metabolism. In addition, caffeine enhances cognitive function and may reduce the risk of neurodegenerative diseases.

As a result, moderate coffee consumption has been linked to a lower risk of type 2 diabetes, stroke, heart disease, certain cancers, liver disease, and depression. However, the question remains: why did coffee with a small amount of sugar show even better results? Researchers believe that a small amount of sugar (one teaspoon) is not enough to cancel out the large benefits of coffee. But this needs further confirmation.

Important Caveats: Not a License to Add Excess Sugar

The researchers emphasize that these results do not mean adding sugar to coffee is beneficial in itself. The study observed an association, not a direct causal relationship. It is possible that people who regularly drink sweetened coffee also have a generally healthier lifestyle. Furthermore, the amount of sugar used in the study was very small (one teaspoon per cup).

In contrast, ready-made coffee drinks from major chains contain much larger amounts of sugar. A single drink can contain 20 to 50 grams of sugar. This far exceeds health recommendations. The World Health Organization recommends that free sugars should be less than 10 percent of daily calories. For an average adult, that is about 50 grams (12 teaspoons) per day. The ideal amount is less than 5 percent (25 grams or 6 teaspoons).

Therefore, researchers advise drinking coffee black or with a very small amount of sugar (no more than one teaspoon per cup). Avoid heavily sweetened drinks, heavy cream, and flavored syrups. Home brewing is preferable for better control of ingredients. Individuals with insomnia, anxiety, or stomach issues should consult their doctor.

Frequently Asked Questions About the Sweetened Coffee Study

Q: Does this study prove that adding sugar to coffee is healthy?

A: No. The study found a statistical association, not a causal relationship. The amount of sugar used was very small (one teaspoon per cup). A generally healthy lifestyle may also play a role.

Q: What is the optimal amount of coffee per day according to the study?

A: The optimal range is 1.5 to 3.5 cups per day. This amount was linked to the largest reduction in death risk.

Q: Do the results apply to instant coffee?

A: Yes, the study included various types of coffee. However, benefits are usually greater with filtered or freshly ground coffee.

Q: What is the daily sugar limit according to global guidelines?

A: The WHO recommends less than 10 percent of daily calories (about 50 grams or 12 teaspoons). The ideal is less than 5 percent (25 grams or 6 teaspoons).

Q: What about coffee with artificial sweeteners?

A: The results were inconclusive. There is not enough evidence of benefits or harms from this study.

Q: Can I drink sweetened coffee from commercial coffee shops?

A: Most coffee shop drinks contain very high amounts of sugar (20 to 50 grams). This may cancel out potential benefits and increase health risks. It is better to order black coffee or add a small amount of sugar yourself.

Prepared by: Scientific News Unit – Qahwa World – based on a study published in Annals of Internal Medicine on May 31, 2022, and the accompanying press release from the American College of Physicians.

Disclaimer: This information is for educational purposes and does not replace medical advice.

Publication date: June 3, 2026

One Cup Can Prolong Life: Morning Coffee as a Key to Longevity

Posted on by Qahwa World

Dubai – Qahwa World

Coffee is one of the most beloved beverages in the world, and millions of people can’t imagine starting their day without it. But according to a new study by Tulane University and the U.S. National Heart, Lung, and Blood Institute, the health benefits of coffee depend not only on how much you drink — but also on when you drink it. The researchers found that a morning cup of coffee may actually extend your lifespan, while drinking coffee throughout the day could reduce its positive effects.

Coffee and Longevity

The study followed more than 40,000 participants for nearly a decade. Those who drank coffee only in the morning had a 16% lower risk of cardiovascular disease and a 31% lower overall mortality rate compared to people who drank coffee at different times of the day. This benefit remained consistent even after adjusting for factors like diet, exercise, and sleep habits.

Why Morning Coffee Works Best

The secret lies in the body’s biological rhythms. Caffeine affects melatonin — the hormone responsible for sleep. When consumed late in the day, caffeine can disrupt circadian rhythms, cause poor sleep, raise blood pressure, and increase stress.
In contrast, morning coffee works in harmony with the body’s natural rhythm, stimulating the nervous system, boosting metabolism, and improving focus right when the body naturally prepares for activity.

Morning vs. Evening Coffee

  • Morning coffee — boosts alertness, speeds up metabolism, lowers cardiovascular risk.

  • Evening coffee — may disrupt sleep, increase blood pressure, and trigger inflammation.

Chronic sleep deprivation caused by late caffeine intake is one of the leading contributors to premature aging, making timing a key factor in coffee’s health impact.

How to Drink Coffee for Maximum Benefit

  • Have your first cup 30–60 minutes after waking up, when cortisol levels naturally drop.

  • Avoid coffee after 2:00 p.m., especially if you’re prone to insomnia or caffeine sensitivity.

  • Choose medium-roast Arabica, which is smoother and less acidic.

  • Limit sugar and cream — they reduce coffee’s health benefits.

  • Drink a glass of water with each cup to stay hydrated.

Common Mistakes and Healthy Alternatives

  • Mistake: Drinking coffee all day for energy.
    Result: Anxiety and nervous fatigue.
    Alternative: Replace your second cup with herbal tea or lemon water.

  • Mistake: Drinking coffee on an empty stomach.
    Result: Stomach irritation and acidity.
    Alternative: Eat a light breakfast — oatmeal, yogurt, or a banana — before coffee.

  • Mistake: Drinking very strong espresso.
    Result: Blood pressure spikes and rapid heartbeat.
    Alternative: Switch to filter coffee or Americano for a gentler caffeine dose.

Should You Quit Coffee Altogether?

Participants who completely avoided coffee didn’t show better health outcomes. In fact, moderate caffeine consumption enhances the body’s antioxidant defenses. However, if coffee triggers anxiety, heartburn, or insomnia, it’s better to switch to chicory, matcha, or green tea, which gently energize without side effects.

Pros and Cons of Coffee

Pros:

  • Improves focus and alertness.

  • Reduces risk of type II diabetes.

  • Enhances mood and physical performance.

  • Rich in antioxidants that slow cellular aging.

Cons:

  • May disrupt sleep and circadian rhythm.

  • Raises blood pressure with overconsumption.

  • Causes dependence and withdrawal symptoms.

  • Irritates the stomach when consumed on an empty stomach.

FAQs

When is the best time to drink coffee?
Between 9:00 a.m. and 11:00 a.m., when cortisol levels naturally decline.

How many cups per day are safe?
Two to three cups daily (up to 300 mg of caffeine), avoiding consumption after noon.

Coffee with milk or without?
If you tolerate lactose, milk can be added — it softens caffeine’s effect. Avoid sugary syrups and heavy cream.

Myths and Facts

  • Myth: Coffee dehydrates the body.
    Fact: In moderate amounts, coffee doesn’t cause dehydration.

  • Myth: Coffee is bad for the heart.
    Fact: Morning coffee can actually lower the risk of heart disease when consumed moderately.

  • Myth: Coffee prevents weight loss.
    Fact: Caffeine boosts metabolism and helps control appetite.

Fascinating Coffee Facts

  • Coffee is the second most consumed beverage in the world after water.

  • Arabica contains almost half the caffeine of Robusta, but is prized for its smooth flavor.

  • The first coffeehouses appeared in Mecca in the 15th century, and coffee became fashionable in Europe in the 17th century.

Modern science now confirms what coffee lovers have always felt instinctively:
A morning cup of coffee isn’t just a habit — it’s a companion to health and longevity when enjoyed wisely and in tune with your body’s rhythm.

New Study Reveals Shocking Findings on How Hot and Cold Coffee Affect the Body and Mind

Posted on by Qahwa World

Dubai – Qahwa World

A groundbreaking study published in the British Journal of Nutrition has uncovered a surprising link between the temperature of beverages—particularly coffee—and human physical and mental health. The research suggests that the difference between a steaming cup of coffee and an iced drink goes far beyond taste, extending to real effects on mood, digestion, and sleep.

Conducted by researchers from San Diego State University, the University of California San Diego, and Wake Forest University under the direction of Professor Tianying Wu, the study involved more than 400 healthy adults of Asian and White backgrounds between the ages of 18 and 65. The goal was to determine how the temperature of foods and drinks affects emotional and physical well-being. Participants reported how often they consumed cold and hot drinks such as water, coffee, tea, milk, and juice, as well as hot and cold meals during summer and winter. They also recorded symptoms related to anxiety, depression, insomnia, and digestive issues such as gas and abdominal fullness.

The results were striking. Among Asian participants, frequent consumption of cold beverages and foods—especially during the summer—was associated with higher levels of anxiety, sleep disturbance, and digestive discomfort. Those who reported having cold hands, an indicator of poor blood circulation, experienced these negative effects more strongly. The findings suggest that cold consumption in warm months may intensify anxiety and insomnia, while no significant benefit was found from hot consumption within this group.

In contrast, White participants showed the opposite trend. Those who preferred hot drinks, particularly during winter, reported fewer symptoms of depression, insomnia, and gastrointestinal discomfort. Regular consumption of hot coffee or tea during colder months was linked to better mood, improved sleep, and reduced bloating or gas. Meanwhile, higher intake of cold drinks and foods corresponded with higher anxiety and poorer sleep, particularly among those with low body warmth or poor circulation.

The researchers note that these findings align with ancient perspectives in traditional Chinese and Ayurvedic medicine, which warn against consuming cold foods and beverages during winter and emphasize the health benefits of warmth. While Western medicine rarely considers temperature as a health factor, this study offers scientific evidence that thermal effects can influence human physiology.

According to the authors, cold drinks can lower core body temperature, slow gut activity, and disrupt the balance of gut microbiota, all of which may impair digestion and mood. Exposure to cold also constricts blood vessels and reduces oxygen flow to the brain, potentially heightening anxiety and disturbing neurotransmitter balance. Conversely, warm drinks stimulate blood circulation, support healthy digestion, and activate the parasympathetic nervous system—responsible for relaxation—thus improving mood stability and sleep quality.

While the study is observational and does not establish causation, the patterns are consistent enough to warrant attention. The researchers emphasize that individual factors—such as poor circulation or cold extremities—can make some people more vulnerable to the negative effects of cold consumption.

Interestingly, even within the Asian group, the differences were notable. Chinese participants, who reported the lowest intake of cold foods and beverages, also showed the fewest symptoms of anxiety, depression, and digestive issues. Indian participants, on the other hand, displayed stronger associations between cold consumption and adverse health outcomes. The study further observed that Asian immigrants who had lived longer in the United States were more likely to adopt Western dietary habits, including higher consumption of cold drinks.

The authors conclude that the temperature of what we eat and drink is not merely a matter of taste—it may influence our physical and mental balance more than we realize. The findings suggest that warm foods and beverages could promote mental and digestive well-being, particularly during colder months or among individuals sensitive to cold. As Professor Tianying Wu stated, “The temperature of what we consume may matter far more than we think—it can subtly influence our mood and health in unexpected ways.”

Health Differences Between Hot, Cold, and Iced Coffee

Posted on by Qahwa World

Dubai – Qahwa World

A recent study, drawing on data from Free Well Health and scientific research published in the journal Foods (Thomas Jefferson University – 2020), revealed clear differences between hot, cold, and iced coffee in terms of health value, flavor profile, and caffeine levels.

The study noted that all three types contain important antioxidants, but choosing the most suitable one depends on individual factors such as caffeine tolerance, preparation method, and additives like sugar and milk, which can increase calorie content and turn coffee into something closer to a liquid dessert.

Acidity and Nutritional Value

The research showed that cold brew coffee is slightly less acidic than hot brew at the same roast level, but the difference did not exceed 0.2 to 0.34 pH units. Darker roasts had the most significant effect in reducing acidity, making them a better choice for those sensitive to acids.

Hot coffee was also found to be richer in antioxidants, with levels remaining stable even with darker roasts. In contrast, antioxidant capacity in cold brew decreased as roast levels darkened. The study also revealed that hot coffee contained higher total dissolved solids (TDS), giving it a fuller body and more pronounced flavors, while cold brew offered a smoother texture and lower acidity, making it gentler on the stomach and teeth. Iced coffee, meanwhile, is essentially hot coffee that has been cooled and served with ice, offering refreshment without major changes in nutritional value.

Caffeine content remained similar across all three types when brewed in the same proportions, with averages of about 205 mg in a large cold brew compared to roughly 165 mg in iced coffee, while hot coffee was closer to the iced version. This indicates that cup size and coffee-to-water ratio play a bigger role in caffeine strength than the brewing method itself.

What Does This Mean for Coffee Lovers?

For those who want less acidity: A medium or dark roast is the best option, with cold brew providing a slightly lower acidity than hot.

For those focused on antioxidants: Hot brewing remains more consistent across roast levels.

For those seeking smoothness and mildness: Cold brew delivers a softer texture and lower acidity but is generally less concentrated.

For those worried about caffeine: There’s no major difference between hot and cold brews; cup size and ratio matter more.

In conclusion: The main differences among hot, cold, and iced coffee lie in acidity, antioxidant content, and texture, while caffeine remains largely unchanged — giving consumers the freedom to choose based on taste preference and health needs.

German–UK Study Finds Morning Coffee Boosts Positive Mood and Relieves Withdrawal Symptoms

Posted on by Qahwa World

Dubai – Qahwa World

A new scientific study published in Scientific Reports has revealed that the morning cup of coffee does more than increase alertness: it significantly enhances positive mood, making people feel happier and more enthusiastic in the early hours of the day.

Conducted by researchers from Bielefeld University in Germany and the University of Warwick in the United Kingdom, the study provides strong evidence that caffeine is closely linked to improved well-being, particularly in the morning.

The research tracked 236 adult participants across two separate studies.

  • The first study involved 115 participants over 14 days, resulting in 8,335 individual mood assessments.

  • The second study involved 121 participants over 28 days, generating nearly 19,960 assessments.

Using the Experience Sampling Method (ESM), participants were asked to record their mood seven times a day on their smartphones. They also noted whether they had consumed a caffeinated drink in the previous 90 minutes.

Key Findings

  • Caffeine consumption was strongly associated with higher positive mood (happiness, enthusiasm, and energy), especially during the first 2.5 hours after waking up.

  • The impact on negative mood (feelings such as sadness, anger, or irritation) was minimal and less consistent.

  • Results were consistent across different levels of caffeine intake and were not significantly affected by whether participants reported sleep disturbances, anxiety, or other psychological conditions.

  • Researchers suggested that the morning effect could partly be due to reversal of mild overnight caffeine withdrawal symptoms, as even moderate consumers may wake up experiencing them.

Scientific Explanation

Caffeine improves mood through two main mechanisms:

  1. Blocking adenosine receptors in the brain, reducing drowsiness and boosting alertness.

  2. Stimulating dopamine production, a neurotransmitter known as the “happiness hormone,” which is linked to motivation and reward.

Professor Anu Realo, a co-author of the study, explained:

“Even moderate caffeine consumers may experience mild withdrawal symptoms that disappear with the first cup of coffee in the morning.”

Lead researcher Jostin Hachenberger added that caffeine’s mood-enhancing effect was largely independent of social or psychological factors but could be influenced by physical conditions, such as fatigue.

Critical Notes

  • Since most participants were habitual caffeine consumers, the study could not determine how coffee might affect people who completely avoid caffeine.

  • The findings do not support the claim that caffeine worsens anxiety; rather, the researchers noted that those who are sensitive to caffeine’s negative effects usually self-select out by avoiding it.

Global Context

  • Approximately 80% of adults worldwide consume coffee or tea daily, highlighting the global significance of these findings.

  • Interestingly, caffeine’s appeal is not limited to humans: previous studies have shown that bees and wasps are attracted to nectar containing caffeine, underlining its powerful influence in nature.

Conclusion

The study concludes that the morning cup of coffee is more than just a daily ritual. It has a scientifically measurable impact on enhancing positive mood and boosting emotional well-being, particularly in the hours after waking. While it may not significantly reduce negative emotions such as sadness or anger, its role in fostering happiness, enthusiasm, and energy makes coffee one of the most influential beverages in modern life.