New research suggests an early intervention with two common, low cost drugs could be lifesaving after a heart attack. PixelCatchers/Getty Images
A new study found that adding a second drug early after a heart attack may save lives.
Those who added ezetimibe to a statin had fewer complications and deaths.
The authors say that early combination therapy should become the standard of care.
Experts say addressing underlying inflammation can also help control cholesterol.
New research from Sweden suggests that starting a second cholesterol-lowering drug soon after a heart attack may help save lives.
According to the study, published in the April 2025 issue of the Journal of the American College of Cardiology, people who received ezetimibe (brand name Zetia) with their statin therapy within 12 weeks of a heart attack had fewer heart-related complications and deaths than those who waited longer or never added ezetimibe at all.
The National Library of Medicine explains that ezetimibe helps reduce the amount of low-density lipoprotein (LDL) cholesterol in your blood by preventing cholesterol from being absorbed in the small intestine.
LDL cholesterol is the so-called “bad” cholesterol associated with clogged arteries and an increased risk of cardiovascular diseases such as heart attack and stroke.
Ezetimibe is sometimes prescribed for people who can’t tolerate statins. It may also be used as an add-on treatment when statins do not sufficiently lower cholesterol.
This medication works differently from statins, which exert their cholesterol-lowering effects by slowing down the liver’s production of the waxy substance.
Early combination therapy after heart attack may save lives
To arrive at their conclusion, the researchers analyzed data from more than 35,000 patients hospitalized for heart attacks (myocardial infarction) between 2015 and 2022, using the comprehensive SWEDEHEART registry in Sweden.
Most patients were prescribed high-intensity statins at discharge, but a subset also began taking a second medication, ezetimibe, within the first 12 weeks after discharge.
The study categorized patients into three groups: those who started ezetimibe early (within 12 weeks), those who started late (13 weeks to 16 months after discharge), and those who never received ezetimibe during this period.
Importantly, the analysis used advanced statistical methods — specifically, a clone-censor-weight framework — to emulate a randomized clinical trial and minimize biases
Results showed that patients who started ezetimibe early in combination with statins had a significantly lower risk of major adverse cardiovascular events (MACE), which include death, another heart attack, or stroke, compared to those who delayed ezetimibe or never took it.
One-year incidence rates of MACE were 1.79 per 100 patient-years in the early ezetimibe group, compared with 2.58 in the late group and 4.03 in those without ezetimibe.
At three years, the hazard ratio for MACE was 1.14 for late versus early treatment (not statistically significant) but was 1.29 for no ezetimibe versus early treatment, indicating substantially higher risk without ezetimibe.
Cardiovascular death was also significantly higher in the late and no ezetimibe groups compared to early treatment.
Additionally, early combination therapy led to a greater proportion of patients achieving guideline-recommended LDL cholesterol targets (<1.4 mmol/L or <55 mg/dL) within one year.
What are the implications for heart attack patients?
The study underscores that a stepwise approach — starting with statins and adding ezetimibe only if LDL cholesterol goals are not met — inevitably delays optimal cholesterol lowering and is associated with avoidable harm.
As the authors note, approximately 75–80% of post-heart attack patients fail to reach LDL goals with statin therapy alone; initiating combination therapy early can improve outcomes and reduce future cardiovascular events.
To maximize protection, the researchers advocate that care pathways for heart attack patients should be updated to implement early combination therapy with statins and ezetimibe as standard care, potentially even before hospital discharge.
Arun Manmadhan, MD, assistant professor of cardiology at Columbia University Irving Medical Center, who was not involved with the study, said the findings align with a broader body of research showing that sustained, low LDL cholesterol levels are associated with fewer heart attacks and strokes.
“This is even more important in people who have already experienced one of these events,” he said, “because lowering the cholesterol levels, in addition to optimizing other cardiac risk factors, is one of the most effective and proven ways to prevent a second event.”
Manmadhan said that, in his opinion, this study adds to the evidence that patients who have had a heart attack or stroke should have their cholesterol levels aggressively managed, both through lifestyle and medications.
“This study suggests that time is also an important factor,” he added. “[The] earlier and faster cholesterol levels are aggressively controlled to recommended levels after a heart attack, the better it is for preventing future cardiovascular events.”
What can patients do beyond cholesterol-lowering drugs?
Markyia Nichols, MD, MPH, RDN, a CDC-certified lifestyle coach and chief medical officer at Ciba Health, said patients should know that “cholesterol isn’t the enemy.”
“It’s a response,” she explained. “Cholesterol is essential for life. It builds hormones, stabilizes cells, and repairs tissue. If cholesterol is rising, it’s critical to ask what the body is trying to repair or protect against.”
According to Nichols, inflammation is the real problem, not cholesterol. A diet high in sugar, processed seed oils, and ultra-processed foods, insulin resistance, metabolic dysfunction, chronic stress, and exposure to toxins can all factor into creating inflammation.
“Once the heart lining is damaged, the body sends cholesterol as a patch,” she said. “Cholesterol doesn’t cause the ‘fire.’ It acts more like the ‘firefighters.’”
Nichols added that, digging deeper, LDL only becomes dangerous when it’s oxidized due to poor nutrition.
Circling back to the study, she told Healthline that while adding ezetimibe to statins post-early heart attack may lower cholesterol, it’s not addressing the root causes of the problem. Patients also need to focus on nutrition.
“Ask for labwork that tests levels of magnesium, omega-3s, vitamin D, and vitamin K2,” she advised. “You can’t rebuild a healthy heart without healthy raw materials.”
She also suggests looking to see whether your markers of inflammation, such as C-reactive protein, homocysteine, and insulin, are high.
Further, look for any sources of inflammation you might have, like a poor diet, stress, toxins, or an unhealthy gut.
Nichols concluded by saying that you may need to see a board-certified doctor trained in root-cause medicine to determine what’s causing your inflammation.
However, addressing this can help you heal the underlying causes of your high cholesterol.
Health agencies and experts recommend fluoride in drinking water at low levels (currently 0.7 mg/L in the U.S.) to promote dental health. LukaTDB/Getty Images
HHS Secretary Robert F. Kennedy Jr. called for a ban on fluoridated water in U.S. communities.
Emerging evidence shows potential health harms and neurotoxic effects in young children, but experts caution these studies are limited and the findings should be interpreted with caution.
Experts have called for more robust studies on the potential health effects of fluoridated water in Americans.
Health agencies recommend fluoride in drinking water at low levels (currently 0.7 mg/L in the United States) to promote dental health.
The debate over the safety of fluoride in drinking water was reignited earlier this month when Health and Human Services Secretary Robert F. Kennedy Jr. proposed a ban on fluoridated water in communities across the United States.
In tandem with the health secretary’s announcement, the Environmental Protection Agency (EPA) announced at a press conference in Salt Lake City on April 7 that it would review “new scientific information” about the purported health risks of fluoridated water.
The EPA is responsible for setting the maximum levels of fluoride allowed in public drinking water, which is currently 0.7 milligrams per liter (mg/L), according to the Centers for Disease Control and Prevention (CDC).
Kennedy’s move coincides with a recent ban in Utah, the first state to prohibit fluoride in drinking water.
Kennedy told The Associated Press that he plans to assemble a task force to investigate the issue and draft new recommendations on fluoridated water.
While Kennedy cannot outright ban fluoridation across U.S. communities, he could order the CDC to change its recommendation. He can also work with the EPA to change the maximum threshold of fluoride in drinking water.
Fluoride, a naturally occurring mineral, was first added to water in U.S. communities in the mid-1940s to protect dental health, particularly in areas with limited access to dental care.
These health agencies attest that the current designated levels of fluoride in drinking water are safe and that fluoride toothpaste and supplements are safe for use in age-appropriate amounts.
“When government officials, like Secretary Kennedy, stand behind the commentary of misinformation and distrust peer-reviewed research, it is injurious to public health,” Brett Kessler, DDS, president of the American Dental Association, said in a statement.
“Let’s stop the rhetoric and comprehensively study fluoride at the optimal level once and for all,” he said.
Research on the effects of fluoride exposure is limited and ongoing. The problem with the current literature is a lack of substantial evidence supporting the potential health harms to populations within the United States, most notably the possible neurotoxic effects in children.
Adding to the confusion, fluoride levels are much higher in many countries outside the United States, where research on fluoride exposure is more common. What’s more, most European countries and some provinces in Canada do not add fluoride to drinking water at all.
Despite advancements in dental care and the unknowns about potential health effects, many people may wonder why fluoride is still in our drinking water.
“What’s happened over the past, say, two decades is that there has been growing evidence that fluoride exposure in children, and in particular, in the developing child, is neurotoxic,” said Bruce Lanphear, MD, MPH, professor of health sciences at Simon Fraser University in British Columbia, Canada.
“That is, it’s associated with diminished IQ scores, which is very much along the lines of what we’ve seen with lead in children. Should we expect universal agreement? Absolutely not. We don’t see a universal agreement with lead. We see more agreement with lead, but we have a much more stable measure of lead,” Lanphear told Healthline.
What are the health risks of fluoride exposure?
In 2015, the amount of fluoride added to water to prevent tooth decay was lowered from 1.2 mg/L to 0.7 mg/L due to increased fluorosis in children in recent decades.
Rates of dental fluorosis, a common condition that causes tooth discoloration and brown and white spots on permanent teeth, have nearly doubled among adolescents in the United States.
“It seems to have plateaued,” Lanphear said of the condition, “but it has increased quite a bit, and the only reason is [children are] getting too much fluoride.”
Health Secretary Kennedy’s position on fluoride may be partially influenced by a recent global study published in January in JAMA Pediatrics. The study suggests that children exposed to higher fluoride levels in water had lower IQs, igniting controversy among health experts on both sides of the ongoing discussions over its safety.
Fluoride proponents note these findings are based on exposure in children in non-U.S. countries, mainly in China and India, where fluoride levels are much higher. The American Dental Association urged the public to interpret the findings with caution.
“I think there’s been a lot of fear that’s been instilled by RFK Jr. and his associates,” said Danelle Fisher, MD, FAAP, board certified pediatrician at Providence Saint John’s Health Center in Santa Monica, CA.
“We need to start by ensuring people that currently they are safe and that we have effective ways to keep their kids healthy and safe. In the case of dental health, it’s correctly fluoridated water — and we do see good dental health with the kids who are exposed to our water and fluoridated toothpaste,” she told Healthline.
The JAMA Pediatrics study followed the release of a massive report from the National Toxicology Program published in August 2024 by the National Institutes of Health. Similarly, the report linked high levels of fluoride exposure in children to a small decrease in IQ, prompting opponents to reevaluate current fluoride levels in U.S. water systems.
However, the report notes flaws in its study, citing insufficient data to determine whether the current low fluoride level of 0.7 mg/L in U.S. community water systems negatively affected children’s IQ.
“We have growing evidence that fluoride is neurotoxic because kids are getting too much fluoride, as evidenced by increasing rates of fluorosis, and because there’s now new evidence that fluoride is not effective when added to water at preventing tooth decay,” Lanphear said.
Lanphear, who co-wrote an accompanying editorial to the JAMA Pediatrics study, cited a 1995 animal study that found fluoride was associated with behavioral deficits in rats.
“Many of the early studies were cross-sectional and not particularly high quality. And that’s been one of the major criticisms of this new evidence — but it really shouldn’t be a criticism, because that’s how most science evolves,” Lanphear said.
Indeed, many studies examining fluoride toxicity have been small in scale and were conducted in animals and in vitro.
Still, researchers have sounded alarm over the potential threats of fluoride exposure to human health. Many have cited dental fluorosis as a complication, while others have observed more serious effects.
A 2022 review of the literature suggests exposure to fluoride at levels much higher than the current 0.7 mg/L level in the United States or the maximum threshold of 1.5 mg/L set by the WHO could lead to a range of issues, such as:
skeletal fluorosis
arthritis
bone damage
osteoporosis
muscular damage
fatigue
joint-related problems
chronic health issues
damage to vital organs
endocrine or thyroid disruption
Still, as with other fluoride studies, these findings are limited and may be easily misinterpreted. For instance, the fluoride levels studied in the 2022 review exceeded the U.S. and global thresholds for fluoride in water. And of course, animal studies do not necessarily translate to humans.
Due to the limited nature of fluoride research, health experts and scientists remain divided on whether fluoride should remain in public drinking water or be removed entirely.
Inderpal S. Randhawa, MD, board certified internist, immunologist, pediatrician, pediatric pulmonologist, and medical director of the Children’s Pulmonary Institute at MemorialCare Miller Children’s & Women’s Hospital Long Beach in Long Beach, CA, noted the risk of tooth decay and poor dental hygiene still exists in some parts of the United States.
He told Healthline that Kennedy’s proposed ban on fluoridated water seemed reasonable in communities with widespread access to dental care and fluoride-based toothpaste. In areas with poor dental health, however, fluoride levels should remain as low as possible, he said.
“The concerns are real,” Randhawa said. “Long-term, systemic fluoride exposures can result in an excess amount of fluoride in the body. This can impact the bones, thyroid, and other organ systems. Reducing this risk in today’s advanced dental care is something to consider.”
Fisher said the current fluoride levels are safe but called for more studies with U.S. children to better understand the potential risks.
“It’s always important to look at whatever research is coming out and base our recommendations on what we think is in the best interest of the children who need this fluoride for good dental health — but obviously, we never want to do harm,” Fisher said.
“So, if there is compelling evidence that comes out that the fluoride supply in the water in the U.S., for instance, is too high and is leading to a decrease in IQ, which could potentially lead to cognitive decline, that is important information to know. The problem with making conclusions from the [JAMA Pediatrics] study is that it might be misguided.”
Fisher noted that the JAMA Pediatrics findings are based on countries with almost double the amount of fluoride in their water supplies.
“There’s nothing in there that studied children in the U.S., but since this is being cited as evidence, it is important not to create hysteria amongst families. If we’re going to do research that’s going to directly correlate IQ scores and fluoride exposure in the U.S., let’s do that study,” she said.
“Over time, we recognized there is an importance to having fluoride in our water supply. Adding fluoride to the water in an adequate amount was important to improve dental health. That is something that has absolutely been shown and demonstrated, especially here in the U.S.,” Fisher noted.
Fluoride exposure in adequate amounts appears safe
Many health experts agree that intermittent fluoride use appears safe and effective.
“As opposed to drinking fluoride in water where the exposure is systemic, local application with toothpaste-like products is much lower exposure,” Randhawa said. “Similarly, receiving such treatments at the dentist is minimal exposure.”
Fisher said that before fluoride was introduced to drinking water, dental and other health problems were significant in areas with scarce access to fluoride and proper dental care.
“When we didn’t have fluoride in the water, we saw so much more teeth problems and subsequent problems that came from that,” she said.
“The amount of dental decay and disease was rampant, and it is rampant in parts of the world where kids don’t have access to fluoride. Dental problems don’t just affect the teeth, they affect the entire child. We are talking about kids who would go on to potentially develop brain problems, brain abscesses that spread from dental decay,” Fisher explained.
Lanphear shared a different perspective, noting the risks of water fluoridation may outweigh the potential benefits.
“The evidence about the effectiveness of water fluoridation or systemic fluoride has never been rigorous,” he said, citing a large systematic review published in 2024 in Cochrane Review.
Researchers examined evidence dating back to 1975 on whether water fluoridation is effective in reducing tooth decay. They found that fluoridated water had little to no benefit in preventing cavities, maybe a 3% to 4% reduction, Lanphear noted, which meant it was not statistically significant. This, he said, questions the benefit side of the equation.
Lanphear also cautioned against fluoride-based toothpaste for young children, which contradicts current pediatric recommendations. “Children 1 to 4 years old might be getting 80% of their fluoride from swallowing toothpaste,” he surmised.
Be that as it may, fluoridated water remains at very low levels in U.S. communities for now, and pediatric dentists continue to recommend fluoride-based toothpaste.
Pediatricians like Fisher recommend that children under 6 years old use a pea-sized amount of fluoridated toothpaste twice daily. Fisher said pediatricians and dentists consider this a safe amount to ingest if swallowed since most young children do not know how to spit.
“Are we swallowing too much toothpaste? There’s no evidence to show that we are. However, if studies are done in the future that do demonstrate that, we will adjust our recommendation, but currently, there’s no need to panic,” she said.
More studies on fluoride exposure needed
Fisher reiterated that the fluoride levels in U.S. water systems are adequate but urged further study of the potential effects.
“Let’s look at how we as a society, as Americans, can best supply a good amount of fluoride to our kids so their teeth and brains are healthy,” she said.
“It would be great to see a prospective study of American children, meaning you look at them first and then follow them over time and watch their developments, and you can measure IQ, if you want,” she said.
Fisher noted there are other ways to assess cognitive development that don’t involve IQ scores.
“I think those studies will be interesting and important, and potentially, if we find out that the amount of fluoride in our water is too much or not enough, we can adjust it accordingly,” she said.
Lanphear agreed that more research on fluoride, in general, is needed, but opposed fluoridated water.
“I think, at a minimum, what we can say is it’s time to convene an independent scientific panel to review the evidence on the safety and purported benefits of water fluoridation,” he said.
“Fluoride toothpaste is efficacious, based upon good, rigorous, randomized, controlled trials. Drinking it or taking it as a supplement does not appear to be efficacious. So given all of that, if you ask me, and I had to make that decision as an individual, I’d say, absolutely take it out of the water,” Lanphear said.
Fisher, on the other hand, remained optimistic about the low levels of fluoride in water and offered reassurance about current best practices for dental health.
And if there is one thing most, if not all, experts agree on, it’s that more research on the effects of fluoride exposure is needed.
“Scientists are here to make sure that we have good health, for ourselves, for our children. Nothing is more important,” Fisher said. “We do need fluoride. We need a good amount, and we should not panic about this.”
Moderate daily exercise significantly reduced the risk of death from cardiovascular disease among female cancer survivors, a new study found SolStock/Getty Images
Among older female cancer survivors, moderate daily exercise significantly reduced the risk of death from cardiovascular disease.
Cancer survivors are statistically more likely to develop cardiovascular disease.
Reducing sedentary time and increasing activity can be easily integrated into daily life to lower cardiovascular disease risk.
Staying active and limiting sedentary time is essential to reducing the risk of cardiovascular disease (CVD), but little research exists to show its effects in older female cancer survivors.
Now, researchers have found compelling evidence that getting more daily physical activity has a robust protective effect on heart health for this group.
Moderate daily exercise — through exercise sessions or hitting daily step goals from walking — significantly reduced the risk of death from cardiovascular disease in postmenopausal cancer survivors.
In another promising development from the study, researchers found that exercising at levels below current recommendations showed significant benefits, underscoring that every little bit counts when it comes to exercise.
The findings are essential for the long-term health of cancer survivors, who are at increased risk of CVD compared to other adults.
“While health benefits were maximized at 60 min [per] day of moderate-to-vigorous physical activity and around 5,000–6,000 steps/day, there were substantial health benefits evident at amounts below these levels,” Eric Hyde, PhD, MPH, a research analyst at the University of California, San Diego, and presenter of the research, told Healthline. “Encouraging cancer survivors to sit less and take more steps may help promote long-term survival.”
Moderate exercise reduced death risk from CVD by 60%
Hyde and his team utilized accelerometer data from nearly 2,500 female cancer survivors to see how daily exercise affected all-cause and CVD-related mortality risk.
That data resulted from two studies conducted between 2011 and 2015 and an additional four years of follow-up, collectively known as the Women’s Health Accelerometry Collaboration.
The females involved in those studies were between the ages of 63 and 99, with an average age of 74. They wore a fitness tracker for at least 10 hours per day for up to one week. The device recorded bouts of exercise, step count, and sedentary behavior.
The cohort experienced different forms of cancer, the most prominent of which were breast (52%), endometrial (8.5%), and malignant melanoma (7.1%). Other cancers included:
lung
bladder
ovarian
rectal
bladder
colon
myeloma
kidney
head and neck
When Hyde examined the association between physical activity data from the exercise trackers and mortality, those who exercised or walked more had significantly better health outcomes. Engaging in one hour per day of moderate to vigorous physical activity lowered the risk of death by 40% and the risk of death linked to CVD by 60%.
CDC guidelines and the AHA recommend that adults get at least 150 minutes of moderate-intensity physical activity weekly.
If you count your physical activity in steps rather than time spent exercising, the greatest benefit was seen in participants who clocked 5,000-6,000 steps per day, lowering the risk of death by 40%.
Note this is well below the more commonly touted 10,000 steps per day, a myth that’s been somewhat debunked since the optimal number may depend on your age.
However, the study did find additional benefits of more walking: each additional 2,500 steps per day was associated with a 34% further reduction in the risk of death from CVD.
On the other hand, sedentary behavior was linked to worse health outcomes. For every 102 minutes of sitting per day, participants’ risk of death from all causes increased by 12%, while the risk of CVD-related death jumped by 30%.
“In the past, clinicians used to advise cancer patients to rest and avoid activity when possible,” Hyde said.
“However, the evidence is now clear that those with a history of cancer can greatly benefit from being more physically active. There needs to be increased awareness of the importance of moving more and sitting less among cancer survivors.”
Exercising more, sitting less at any age
Keith Diaz, PhD, an associate professor of behavioral medicine at Columbia University Medical Center and member of the AHA’s Physical Activity Science Committee, not involved in the study, told Healthline that prioritizing health and time management is essential for hitting your daily activity goals.
“We work, we care for kids, we upkeep our living spaces. Yet some find the time for exercise and others don’t, said Diaz. “Instead of thinking of exercise as a structured activity that requires a dedicated time slot, it can help to integrate movement into the daily rhythms of your life.”
Diaz recommended various strategies that can help integrate more activity and less sitting into your daily routine. They include:
“Walk and talk.” Any time you’re on the phone, get some steps in rather than sitting down.
Link exercise to existing habits like meals or entertainment. When you finish your lunch or your favorite Netflix show, take a 5-minute walk afterward.
Try to squeeze in some movement whenever you can rather than fixating on a single exercise.
Eleanor Levin, MD, a clinical professor of cardiovascular medicine at Stanford Medicine, recommended exercising with a social group, such as a walking club, to stay motivated. Levin wasn’t involved in the new research.
Fatigue is a common problem for cancer survivors, so while exercise may seem even more strenuous to begin with, it will help to relieve this common symptom in the long run.
“Paradoxically, regular physical activity is one of the most effective ways to increase energy levels. Even small amounts of exercise can create a positive feedback loop — where exercise improves conditioning, reduces fatigue, and makes future physical activity feel easier,” said Diaz.
Takeaway
Among postmenopausal female cancer survivors, one hour of moderate exercise or 5,000 steps per day significantly reduced the risk of death from all causes and cardiovascular disease, new research shows.
On the other hand, every 102 minutes spent sitting per day was associated with a 30% increased risk of death from cardiovascular disease.
When it comes to exercise, every bit counts. Benefits have been identified even when exercising less than current guideline recommendations.
A new study suggests that probiotics can benefit mental health even in generally healthy populations. vorDa/Getty Images
Taking probiotics may reduce negative mood, according to a new clinical trial.
The study adds more evidence to the gut-brain connection’s role in regulating emotion.
Experts caution that probiotics are not a substitute for psychiatric medication and therapy.
Probiotics reduced negative mood in a new clinical trial, adding to mounting evidence that the gut-brain connection plays a crucial role in mental health.
In the randomized, double-blind, placebo-controlled study, researchers observed that participants began feeling mood improvements within about two weeks of taking probiotics.
Because the study involved healthy adults — not just people with diagnosed depression — the findings suggest probiotics could benefit mental health across the general population.
The researchers noted their use of daily mood tracking may have helped detect subtle improvements that other mental health assessments could miss.
“This is the first study to implement daily mood monitoring to assess the effects of probiotics, and in fact, by the end of the month-long study, their negative mood still appears to be improving,” Katerina Johnson, PhD, first author of the study and a research associate at the University of Oxford in the United Kingdom, told Healthline.
The study adds to growing interest in the gut-brain connection, a complex communication system that is thought to influence mood and emotions between the gut and the brain.
The gut produces a large amount of serotonin (about 95%), a neurotransmitter involved in everything from mood to appetite. This suggests that improving gut health could positively impact mental health.
Probiotics improved negative mood
Researchers conducted a comprehensive study involving 88 healthy volunteers with an average age of 22. Participants in the study were not overweight, which was based on their body mass index (BMI). They also did not engage in excessive drinking, nor drug use.
Once enrolled, participants were randomly assigned to receive either a multispecies probiotic mixture or a placebo for 28 days.
The probiotic mixture contained nine bacterial strains, including various Bifidobacterium, Lactobacillus, and Lactococcus species. Participants consumed one 2-gram sachet daily dissolved in lukewarm water.
The researchers administered a comprehensive battery of validated psychological questionnaires before and after the four-week intervention, including measures of anxiety (STAI), worry (PSWQ), depression (CES-D), and negative affect (PANAS).
Despite this thorough approach, these standard psychological assessments detected minimal differences between the probiotic and placebo groups.
However, daily mood reporting told a different story.
This daily monitoring revealed the study’s most significant finding: participants who received probiotics showed a reduction in negative mood starting around the two-week mark, while those on placebo showed no such improvement.
“By monitoring people daily, rather than just assessing them before and after, it gives us a much better resolution of changes over time when taking probiotics,” Johnson said.
“One disadvantage with psychological questionnaires is that they attempt to dissect how people are feeling into discrete categories, e.g., stress, anger, anxiety, or depressive tendencies. In contrast, asking how positive or negative someone is feeling can holistically capture a change in any emotional state,” she explained.
These findings suggest that probiotics can benefit mental health even in generally healthy populations and that common research methods may miss these effects. Interestingly, the improvements in negative mood didn’t affect positive mood, which remained unchanged in both groups.
“We certainly understand that while we’ve had treatments for depression and anxiety for years, they’re sometimes not the right fit for an individual,” Lisa Durette, MD, chair of psychiatry at the Kirk Kerkorian School of Medicine at the University of Nevada Las Vegas, told Healthline. Durette wasn’t involved with the research.
“Opening up the discussion around other ways for us to help our patients and taking a more holistic approach is a very good thing,” she noted.
“If you look at the way in which individuals report antidepressants affecting themselves, a lot of patients will say they feel like they are emotionally blunted. They can’t feel the highs and the lows as well as I could without medication. But there was no blunting identified with these probiotics, which I think is interesting,” Durette continued.
According to the study authors, if probiotics could simultaneously reduce negative mood without reducing positive mood, that would prove to be a “notable benefit.”
The researchers also found that certain individuals might respond better to probiotics than others. Specifically, as measured by psychological questionnaires, individuals with higher baseline risk aversion showed the greatest improvement in negative mood when taking probiotics.
Probiotics should not replace mental health treatment
Despite the promising results, experts caution that probiotics are not a substitute for psychiatric medication or therapy.
Probiotics may be a helpful addition to a broader mental health strategy, but they shouldn’t replace proven treatments for conditions like depression or anxiety.
“The results from this study underline that probiotics are certainly not sufficient as a standalone solution in the prevention and treatment of mental illness,” Christoph Thaiss, PhD, assistant professor of pathology at Stanford University, told Healthline.
“It is also important to remember that probiotics are available as nutritional supplements that do not undergo the same rigorous testing for efficacy as FDA-approved drugs,” he added.
Thaiss wasn’t involved in the research but noted that “probiotics could play an important supportive role in the clinical management of mood disorders.”
“It may be helpful for you to supplement what you’re doing with a prebiotic or a probiotic or be more mindful of having more whole foods that could increase healthy gut microbiome organisms,” said Durette.
Still, Durette acknowledged that more research in this area is needed. “We don’t know enough yet to determine whether or not these interventions should be a substitute for a traditional treatment,” she said.
