Alcohol’s complex relationship with health

 New global analysis confirms alcohol’s complex relationship with health: clear cancer risks and chronic liver diseases at any level, mixed evidence for other cardiometabolic conditions 

• High alcohol consumption is associated with increased risk across all 20 health outcomes examined. 

• Alcohol use is associated with increased risk for all ten cancers examined in the study, with risk rising as consumption rises.  

• Even consumption below one standard drink per day was associated with elevated risk for cancers of the pharynx, colorectum, esophagus, breast, liver, pancreas, and prostate.  

• For several cardiometabolic and neurological conditions, including type 2 diabetes, Alzheimer’s disease and other dementias, ischemic heart disease, and stroke, low-to-moderate alcohol intake was associated with modestly lower disease risk. 

• The evidence does not support a single universal “safe” threshold. Drinking guidelines should be informed by up-to-date evidence across the full range of outcomes and tailored to the population at hand.  

A new study from the Institute for Health Metrics and Evaluation (IHME) at the University of Washington provides the most comprehensive and conservative analysis to date of the relationship between alcohol consumption and 20 major health outcomes.  

Published in Nature Health, the analysis confirms that alcohol’s effects on health are not uniform. Risks rise steadily with consumption for some conditions, most notably cancers, while for several cardiometabolic and neurological conditions, low-to-moderate drinking is associated with lower risk in observational studies. At higher levels of consumption, the evidence points to increased risk across every outcome examined.  

The research applies IHME’s Burden of Proof (BoP) meta-analytic framework to 843 cohort and case-control studies published through 2023. The framework carefully accounts for differences across studies and focuses on the most conservative estimate supported by the data. Each alcohol-outcome relationship is then assigned a 0- to 5-star rating to show how strong and consistent the evidence is. 

Even at low levels of consumption, alcohol is linked to higher cancer risk. 

The study found harmful associations between alcohol use and all ten cancers examined, with risk increasing progressively as intake rose. Even consumption below one standard drink per day, or less than 10 grams of pure alcohol, was associated with elevated risk for cancers of the pharynx, colorectum, esophagus, breast, liver, pancreas, and prostate. 

Pharyngeal cancer, excluding nasopharyngeal cancer, showed at least a 105% increase in risk at average consumption levels. Cancers of the larynx, colorectum, and lip and oral cavity showed moderate evidence of harm, with the analysis indicating risk increases of at least 22% to 49%. Alcohol use was also linked to higher risk of cirrhosis and other chronic liver diseases, with at least a 40% increase in risk, and pancreatitis, with at least a 22% increase. The evidence was weaker but still suggested higher risk for lower respiratory infections and tuberculosis. 

Esophageal, breast, liver, pancreatic, and prostate cancers showed weaker but consistent evidence of harm, with risks rising steadily as consumption increased. Of all cancers studied, stomach cancer was the one health outcome needing additional evidence to better understand the strength of the relationship.

Cardiovascular, metabolic, and neurological conditions’ risks varied by level of consumption. 

Cardiovascular, metabolic, and neurological conditions presented a more complex picture. For several non-cancer outcomes, the dose-response relationship was J- or U-shaped, meaning the risk was not the same at every level of drinking. In some cases, low-to-moderate consumption was associated with lower risk compared with no drinking, while higher consumption was associated with greater risk. 

“The science on alcohol and health is genuinely complex,” said Dr. Emmanuela Gakidou, senior author and Professor in the Department of Health Metrics Sciences at IHME. “For cancer, the evidence is consistent and unambiguous: risk rises with any level of alcohol intake. For some cardiometabolic and dementia outcomes, studies suggest small reduced risks at low-to-moderate consumption, but those associations became weaker and reversed at higher levels of drinking. Rather than interpreting these results as an endorsement of drinking, they lay out a complex map of where the evidence is strong, weak, or mixed.” 

Type 2 diabetes and Alzheimer’s disease and other dementias each showed a small reduction in risk, at least 4.5% and 6.4%, respectively. For ischemic heart disease, ischemic stroke, and hemorrhagic stroke, evidence of lower risk at low-to-moderate intake was inconsistent, but risk increased at higher levels of drinking. Atrial fibrillation and flutter showed increased risk, with the analysis indicating at least a 6% increase.  

“Our framework takes a cautious approach by accounting for differences across studies and reporting the smallest plausible effect supported by the data,” said Dr. Xiaochen Dai, lead author and research collaborator at IHME. “For some cardiometabolic and dementia outcomes, the relationship is more complex, and the evidence is weaker, which is exactly what our star ratings are designed to make clear.” 

The findings have implications for public health and drinking guidelines.  

National and international drinking guidelines vary widely, with lower-risk thresholds ranging from roughly 8 to 42 grams per day for women and 10 to 52 grams per day for men. The study found no systematic differences in alcohol-health relationships by sex, suggesting that sex-specific thresholds may not fully reflect the evidence across outcomes.  

The authors note that guidelines should be informed by the most up-to-date evidence across the full range of health outcomes, discourage heavy episodic drinking, and clearly communicate that even low-to-moderate intake is associated with elevated risk for several conditions, especially cancers. 

Public awareness of alcohol’s link to cancer remains relatively low, particularly for conditions that are less often discussed in this context, such as breast and colorectal cancer. Effective public health guidance is needed to clearly communicate the potential health impacts of alcohol and help individuals make more informed decisions about drinking. 

Pediatric flu vaccines significantly reduce number of influenza cases

At a glance:

• Comparison of flu vaccination and diagnosis rates in young children born at different times of year confirm the effectiveness of vaccination.

• Researchers found that for every 100 children between the ages of two and five who receive the vaccine in a given flu season, there are between nine and 14 fewer cases of influenza in that age group.

• Findings underscore the public health benefits of flu vaccines and the scientific value of studying ‘natural experiments.’ 

Pediatric flu vaccines significantly reduce the number of childhood cases of influenza, new research from Harvard Medical School confirms. The findings, published on June 1 in JAMA Pediatrics, show that for every 100 children vaccinated, between nine and 14 fewer children catch the flu.

"In the United States, that's hundreds of thousands, if not a million cases of flu that we can avoid each year," said senior study author Anupam Jena, the Joseph P. Newhouse Professor of Health Care Policy in the Blavatnik Institute at HMS. "That's a huge effect size."

The findings provide additional support for the flu vaccine at a time when childhood vaccines have come under scrutiny in the United States. This January, the U.S. Centers for Disease Control and Prevention removed the annual influenza vaccine, as well as several others, from its childhood schedule of recommended vaccines. That change, which was widely condemned by medical societies and public health organizations, was blocked by a U.S. District Court in March.

"The federal government cited an absence of evidence that they want to see, and so we have provided that," said Christopher Worsham, HMS assistant professor of medicine at Massachusetts General Hospital and first author on the study. "We have randomized data, and it shows that flu vaccines are effective for these young children."

Sorting by birthday

Young children typically have an annual visit to the doctor scheduled around their birthday. For children born in the fall, those visits are a convenient time to get the flu vaccine. But children born in the summer will likely have appointments before the flu vaccine becomes available — they need an additional appointment to get vaccinated.

In previous research, Jena and Worsham found that the additional burden on caretakers results in lower flu vaccination rates in summer-born children. This creates a natural experiment, randomly sorting children into more- or less-vaccinated groups based on the happenstance of when they were born.

The researchers compared insurance claims data for summer-born and fall-born children between the ages of 2 and 5 over five flu seasons between 2016 and 2023. (They skipped the 2020-2021 and 2021-2022 seasons because of confounding factors from COVID-19.)

In each season, fall-born children were more likely to be vaccinated and less likely to catch the flu.

The vaccination rates for children with fall birthdays were between 8.6 and 12.5 percentage points higher than those with summer birthdays and the influenza diagnosis rates were 1.0 to 1.4 percentage points lower.

"Across these five seasons, we see that for every hundred kids who are randomly vaccinated because of when their birthday falls, somewhere between nine and 14 of them avoid a case of the flu that they otherwise would have caught," said Jena, who is also a professor of medicine at Mass General. 

For other illnesses that do not have vaccines, such as the common cold or gastrointestinal viruses, there was no difference in the infection rates of the two groups.

"It comes down to: vaccines work," Worsham said.

More natural experiments

As children get older, birthdays and doctor's appointments stop being so closely aligned. The researchers note that after about age five, the influenza diagnosis rates between fall- and summer-born children start to even out.

"The randomized data we have is limited to these very young children because their doctor appointments are tied to their birthday," Worsham said.

That doesn't mean that the vaccine isn't effective in older children, teenagers, or adults — it definitely is, Worsham said. But after a certain age, birthdays are no longer good indicators of whether someone is more or less likely to have received the flu vaccine, so this experiment can't capture vaccine effectiveness in older groups.

This work is just one example of a randomized experiment that can be found in existing data — there are many similar opportunities across different fields of medicine, the researchers said. Jena and Worsham are frequent collaborators and have co-authored a book, Random Acts of Medicine, on the subject.

"It is impossible to do a randomized controlled trial for every single thing that we want to know and understand," Jena said. "But we have an incredible amount of data out there and there are randomized experiments like this sitting in that data, waiting to be uncovered." 

Hormone therapy use for menopause declines despite proven benefits

 

 Hormone therapy use among women in the U.S. remains low, even though it's an effective treatment for many menopause symptoms, according to a new Mayo Clinic study published in Mayo Clinic Proceedings.

Menopause affects more than 1 million women each year in the U.S., and up to 75% experience symptoms such as hot flashes and night sweats that can last for years. Yet researchers found that use of menopausal hormone therapy has steadily declined over time.

The study found that hormone therapy use dropped from 4.4% in 2007 to 1.7% in 2023. Even among women most likely to benefit — those ages 50 to 59 — only about 3.5% were using hormone therapy in 2023.

"We have strong evidence that hormone therapy is safe and effective for many women, but that hasn't translated into how it's used in clinical practice," says Stephanie Faubion, M.D., director of Mayo Clinic's Center for Women's Health and study author.

Researchers expected hormone therapy use to rebound in recent years as awareness of menopause has increased. Instead, rates remain at their lowest level since the early 2000s, following concerns raised after the Women's Health Initiative trial.  

The new study analyzed nationwide trends in hormone therapy use among women 40 and older between 2007 and 2023 using a large U.S. health database. Hormone therapy use was defined as having at least 180 days of filled prescriptions within a given year.

In addition to the overall decline, researchers found differences across racial and ethnic groups. Use was consistently higher among white women compared with Black, Hispanic and Asian American women. Oral therapies remained the most common, although both oral and transdermal treatments declined over time.

Despite growing public conversation about menopause, the findings suggest that increased awareness has not translated into greater use of the effective treatment.

Researchers say several factors may have contributed to the findings, including ongoing misconceptions about risks, limited menopause training among clinicians, and patient concerns or lack of awareness.

"The abundance of misinformation around hormone therapy is one reason some women are not getting treatment," says Dr. Faubion. "Many are seeking care for symptoms but aren't receiving therapies that could help."

Watch: A recent hormone therapy study for women entering menopause

Hormone therapy is not appropriate for every patient. However, for many women — particularly those younger than 60 or within 10 years of menopause — it remains a safe and effective option for symptom relief. Even low-dose vaginal estrogen, which has a favorable safety profile, remains underused.

Untreated menopause symptoms can affect sleep, mood and overall quality of life. Some women may seek care from multiple specialists without a clear diagnosis or treatment plan. Symptoms also may affect workplace productivity.

Researchers say the next step is to better understand and address the barriers preventing women from receiving appropriate care.

"Despite increased attention on menopause, we still have a long way to go," says Dr. Faubion. "Improving education for both patients and clinicians will be key to closing this gap."

Nutrition’s role in chronic fatigue

Diet and homocysteine may influence fatigue and motivation

Peer-Reviewed Publication

Osaka Metropolitan University

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Dietary imbalance, low B12, and folate may correlate with high homocysteine levels and indicate fatigue and low motivation in participants. 

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Credit: Osaka Metropolitan University

With less time and more work, chronic fatigue has become a moniker of modern society. However, this not only reduces the quality of life but also constitutes as a social issue that affects work efficiency and leads to accidents. On the surface, the cause of fatigue is often attributed to not getting enough rest, but there may be another underlying issue—the lack of proper nutrition.

Taking this into account, a research group led by Professor Hiroaki Kanouchi at Osaka Metropolitan University’s Graduate School of Human Life and Ecology focused on nutritional status and water-soluble vitamin deficiencies found in unbalanced diets. The team hypothesized that a lack of folate (B9) and vitamin B12 may be related to fatigue, and centered their research around homocysteine (Hcy), a biomarker known to increase when these deficiencies are present. Blood concentrations of Hcy, folate, and vitamin B12 in approximately 600 healthy Japanese participants were measured. Participants’ fatigue and motivation were assessed using the Chalder Fatigue Scale questionnaire and Visual Analog Scale. The initial results showed that individuals with higher blood Hcy levels had lower levels of vitamin B12 and folate, regardless of sex.

The researchers then examined the relationship between homocysteine levels and fatigue separately for men and women. In their analysis, factors that may influence fatigue, such as age, sleep duration, workload, and dietary habits, were simultaneously accounted for. The results revealed higher Hcy levels were associated with greater physical fatigue in men and higher levels were associated with decreased motivation in women.

“This suggested relationship between vitamin B12, folate, and fatigue in healthy individuals may represent the first report of its kind,” said Professor Kanouchi. “Blood homocysteine levels have traditionally raised concerns in relation to cardiovascular disease, dementia, and fractures. However, our findings suggest that attention should also be paid to fatigue and motivation in the future. To prevent an increase in homocysteine levels, it is important to avoid deficiencies in vitamin B12 and folate. Maintaining a well-balanced diet on a daily basis is essential.”

The findings were published in Nutrients.  

Key to managing leaky gut could lie in common compound we’re already eating

 When the intestinal lining breaks down, harmful gut bacterial antigens can slip into the bloodstream alongside nutrients. This breach in the gut’s protective barrier, known as "leaky gut," is more than a digestive issue – it’s a sign of inflammatory bowel disease (IBD) and has been increasingly linked to a number of chronic conditions. 

In a study published formally on May 28 in the journal Nature Communications, the team shares how phytic acid (or InsP6), a natural compound found in whole grains, beans, lentils, nuts, and seeds, plays an important role in maintaining the integrity of the intestinal barrier. 

“Phytic acid is something many people already consume daily, especially in plant-rich diets,” said Sujan Chatterjee, a UNLV postdoctoral fellow and lead author on the study. “What’s exciting is that it’s beyond just a dietary component; it also functions as a biologically active molecule that supports gut health.”

Eating fewer protein-rich foods may harm our physical function as we grow older

Researchers have found that consuming lower amounts of protein-rich foods may negatively affect physical functioning as people grow older, underscoring the vital function protein plays in preserving mobility and muscle strength in adulthood.  

In a large aging cohort study published in the journal Nutrients, the researchers report that regular dietary habits, particularly the consumption of protein-rich foods, can influence how well individuals move and perform daily activities later in life.  

The study was jointly conducted by an international team of researchers from the University of Sharjah in the United Arab Emirates, Roskilde University in Denmark, the University of Helsinki in Finland, Shifa Tameer-e-Millat University in Pakistan, King Saud bin Abdulaziz University for Health Sciences in Saudi Arabia, and the Medical University of Vienna in Austria.  

Led by Dr. Rizwan Qaisar, associate professor of muscle cell physiology at the University of Sharjah, the research team analyzed data from more than 38,000 adults aged fifty and above from 27 European countries. The data were drawn from the Survey of Health, Ageing, and Retirement in Europe. Participants were followed over several years, allowing researchers to compare their long-term eating habits with changes in physical strength and daily functioning.  

The results of the analysis prompted the researchers to believe that adults who frequently consumed lower amounts of protein-rich foods, such as eggs, legumes, fish, and chicken, were more likely to develop reduced muscle strength and increased difficulty in performing everyday activities over time.  

“The findings showed that individuals with consistently low protein intake were more likely to report problems with walking short distances, climbing stairs, reaching overhead, or managing routine tasks such as shopping,” said Dr. Qaisar. “These associations were particularly noticeable in older adults, and patterns differed somewhat between men and women.”  

Low protein intake and physical impairments  

Scientists link functional impairments, such as a progressive decline in the ability to perform daily tasks, including climbing stairs, rising from a chair, walking, and maintaining balance, to a consequence commonly associated with aging.  

“Simple movements such as walking, standing up, or carrying groceries require muscle strength, balance, and coordination,” explains Dr. Qaisar. “When protein intake is low over long periods, the body may struggle to maintain these systems, increasing the risk of functional decline and loss of independence.”  

The authors emphasize that these limitations not only diminish independence and quality of life but also elevate the risk of falls, hospitalization, and placement in long-term care facilities. “Functional decline is multifactorial, involving musculoskeletal deterioration, neurological changes, and nutritional deficiencies,” they note.

Importantly, the study examined real-world dietary patterns rather than supplements or restrictive diets. It highlights how everyday foods, such as milk, yogurt, eggs, legumes, fish, and poultry, may collectively support healthier aging when consumed regularly.  

Given that dietary habits can be modified, the researchers emphasize the practical implications of their findings. Identifying older adults with low protein intake could provide an opportunity for early, low-cost interventions aimed at preserving mobility, independence, and overall quality of life. 

“Functional decline and sarcopenia are major aging-related concerns. While protein intake is known to influence muscle health, its longitudinal impact on strength and physical function across age and gender remains underexplored,” they write. “We assessed whether low protein intake correlates with future onset of low handgrip strength (HGS) and physical impairments in older adults.”  

Protein intake and active and independent living  

As populations age worldwide, the authors suggest that attention to simple lifestyle factors, such as routine food choices, may help delay physical decline and support longer periods of active, independent living.  

This large, multi-country study of older European adults found that lower habitual protein intake was independently associated with higher odds of reduced handgrip strength and difficulty performing mobility-related activities.  

The association between protein intake and handgrip strength was stronger in men, whereas functional limitations, such as walking 100 meters, stooping, kneeling, extending the arm above the shoulders, and shopping for groceries, were more commonly reported among women. “These findings indicate an association between habitual protein intake and short-term changes,” the authors noted.  

Dr. Qaisar emphasized that protein is not solely important for athletes seeking to build muscle. Rather, consistent intake from common dietary sources plays a crucial role in maintaining strength and the capacity to perform everyday activities, particularly with advancing age.  

"Altogether, this study demonstrates that lower habitual protein intake is associated with a higher likelihood of short-term incident muscle weakness and functional difficulties among older European adults,” the authors conclude. “These findings suggest that habitual protein intake may play a contributory role in maintaining physical function in aging populations.”

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Journal

Nutrients

DOI

10.3390/nu18071058 

Natural trans fats in dairy do not raise heart disease risk

 Trans fats found naturally in dairy foods such as milk, butter and cheese do not increase the risk of heart disease or type 2 diabetes, a new study has found.  

Researchers analysed evidence from 22 studies involving thousands of people across Europe, Canada and the United States and found that natural trans fats behave very differently in the body from the industrial kind. Unlike industrial trans fats, which are strongly linked to heart disease, those found in dairy appear to pose no risk.  

The first-of-its-kind research, published in the journal Nutrition Research, will also raise consumer’s awareness of this topic and provide clarity on trans fat labelling policies which may cause confusion.  

Professor Ian Givens, one of lead authors, and from the University of Reading, said: "People hear the words 'trans fats' and assume the worst, but the trans fats in your morning milk, yogurt, butter or cheese are not the same as the ones from industrial partially hydrogenated fats. This research should give people reassurance that dairy, eaten as part of a balanced diet, is not something to worry about for your heart."  

Two types of trans fat, two different stories  

Trans fats, a type of unsaturated fat, occur naturally in the milk of animals such as cows, sheep and goats, but can also be made artificially during the production of partially hydrogenated fats. The industrial  type, can be found in some processed and fried foods, are strongly linked to heart disease.  

To test whether dairy trans fats affect heart health, the researchers looked at two types of evidence. The first was ten dietary controlled trials in which people consumed dairy foods with naturally enhanced trans fats and compared with regular dairy foods. Scientists then measured the effect on blood lipid biomarkers, which are used to determine heart disease risk. Across all ten trials, covering trans fat intakes ranging from 1.3 to 13.2 grams per day, there were no meaningful differences in blood lipid levels between trans fat-enhanced dairy foods versus regular dairy foods. 

The second type of evidence came from twelve long-term cohort studies that tracked thousands of people over many years, in some cases more than two decades, and measured the levels of dairy trans fats in their blood. None of these studies found that higher levels of dairy trans fats were linked to a greater risk of heart disease, stroke or cardiovascular death.  

Likewise,  higher levels of dairy trans fats in their blood were  not linked with type 2 diabetes risk. 

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Journal

Nutrition Research

DOI