Science
Do zinc products really help shorten a cold? It's hard to say
You feel a cold coming on, or maybe it’s already upon you: the telltale cough, sore throat and stuffy head. You swing by the drugstore, where a shelf full of over-the-counter products containing the mineral zinc claim to be able to shorten the duration of your symptoms.
The promise of relief is tempting. But is it one these products can make good on?
A new analysis of studies published on zinc and cold viruses concludes that there isn’t enough evidence to say whether over-the-counter zinc treatments have any effect on preventing the common cold.
For those who pop lozenges or inhale nasal sprays once a cold has come on, the available research together indicates that the products may reduce the duration of symptoms by up to two days, said Daryl Nault, an assistant professor at Maryland University of Integrative Health and first author of the paper, published Wednesday by the nonprofit organization Cochrane.
But those studies are so inconsistent in terms of the dosage, type of zinc, patient population and definition of cold symptoms that “confidence in the evidence is mostly low to very low,” the review states. “It is likely that additional studies are required before any firm conclusions can be drawn.”
In other words: Nearly 30 years after zinc lozenges first hit the market, we still can’t say for sure if these things do what they say they do.
“We aren’t saying [zinc] does” have any effect on the common cold, Nault said. “We aren’t saying it doesn’t. We’re saying we need more consistent evidence that is replicable. That’s a cornerstone of good science.”
The age of zinc cold products dawned in 1996, when researchers from the Cleveland Clinic Foundation convinced 100 clinic employees to volunteer as research subjects within 24 hours of developing a cold.
Half were given placebos, and half were given lozenges containing 13.3 milligrams of zinc from zinc gluconate every two waking hours as long as their symptoms persisted. Those receiving the zinc got better after 4.4 days on average, while the placebo group felt sick for an average of 7.6 days.
Most people consume a sufficient amount of zinc, a vital nutrient, through a regular diet. The mineral is plentiful in red meat and poultry, and present in many grains and fruits. (Oysters contain more zinc per serving than any other known food, with a single serving containing nearly 300% of the daily recommended intake.)
Scientists aren’t exactly sure how the mineral works to alleviate cold symptoms. But the idea of an over-the-counter way to shorten the misery of a common cold has proved wildly popular.
Total U.S. sales of zinc products, such as Zicam and Cold-Eeze, were $340 million in 2023, said Hannah Esper, managing editor of the trade publication Nutrition Business Journal. Demand for zinc and other supplements exploded during the COVID-19 pandemic, with sales for zinc growing 168.3% during 2020.
Based in the U.K., Cochrane uses rigorous research methods to evaluate existing scientific evidence and produce reports to help people make decisions about their health, according to its website.
For this review, the Cochrane team looked at 34 studies conducted across 13 countries that examined zinc products and the treatment or prevention of the common cold.
Drawing strong conclusions from the available research is difficult, as the studies tend to measure different things, said author Susan Wieland, an assistant professor at the University of Maryland School of Medicine and director of the Cochrane Complementary Medicine Field.
The cold “is a very common condition that is a difficult one to study,” Wieland said. It comes and goes quickly, making it difficult to enroll research subjects. Dosages and the type of zinc administered to study subjects varied widely.
“The designs of each study are different. So different dosages, different dosage forms, different patient populations, different criteria of exclusion and inclusion, different outcomes [and] definitions of cold,” said Dr. Jason Yee, an antimicrobial stewardship pharmacist at Cedars Sinai Medical Center in Los Angeles who was not involved with the review. “It’s really hard to draw the same conclusion based on different studies.”
Physicians said they weren’t surprised by the findings.
“I agree with the study. … It is consistent with my clinical experience in the hospital,” said Dr. Samia Faiz, an internal medicine specialist at UC Riverside Health. “In general, healthy people may be able to take zinc supplements if they make them feel better or if they get some comfort. They should not take these supplements if they have distaste or stomach upset.”
While over-the-counter zinc products are generally harmless to patients battling colds, said Dr. Pritish Tosh, an infectious disease physician and researcher at the Mayo Clinic, popping lozenges “shouldn’t come at the expense of doing things that really matter, which is getting plenty of rest, plenty of fluids and taking care of yourself.”
So why do we continue to fork over our cash for these things when we don’t really have more than a hunch that they work?
When a cold hits, “it’s natural for consumers to just reach for anything that may help alleviate those symptoms. But average consumers aren’t really educated on the literature and studies that are out there showing that there’s limited evidence and efficacy with these products,” Yee said.
Buying the lozenges or huffing the nasal spray can make us feel like we have more agency in a situation where we’re at the mercy of time and our immune systems, Nault said.
“Having a sense of control makes a lot of people feel better, and feel like they’re doing something,” Nault said. “Even if they aren’t.”
Times researcher Scott Wilson contributed to this report.
Science
Cluster of farmworkers diagnosed with rare animal-borne disease in Ventura County
A cluster of workers at Ventura County berry farms have been diagnosed with a rare disease often transmitted through sick animals’ urine, according to a public health advisory distributed to local doctors by county health officials Tuesday.
The bacterial infection, leptospirosis, has resulted in severe symptoms for some workers, including meningitis, an inflammation of the brain lining and spinal cord. Symptoms for mild cases included headaches and fevers.
The disease, which can be fatal, rarely spreads from human to human, according to the U.S. Centers for Disease Control and Prevention.
Ventura County Public Health has not given an official case count but said it had not identified any cases outside of the agriculture sector. The county’s agriculture commissioner was aware of 18 cases, the Ventura County Star reported.
The health department said it was first contacted by a local physician in October, who reported an unusual trend in symptoms among hospital patients.
After launching an investigation, the department identified leptospirosis as a probable cause of the illness and found most patients worked on caneberry farms that utilize hoop houses — greenhouse structures to shelter the crops.
As the investigation to identify any additional cases and the exact sources of exposure continues, Ventura County Public Health has asked healthcare providers to consider a leptospirosis diagnosis for sick agricultural workers, particularly berry harvesters.
Rodents are a common source and transmitter of disease, though other mammals — including livestock, cats and dogs — can transmit it as well.
The disease is spread through bodily fluids, such as urine, and is often contracted through cuts and abrasions that contact contaminated water and soil, where the bacteria can survive for months.
Humans can also contract the illness through contaminated food; however, the county health agency has found no known health risks to the general public, including through the contact or consumption of caneberries such as raspberries and blackberries.
Symptom onset typically occurs between two and 30 days after exposure, and symptoms can last for months if untreated, according to the CDC.
The illness often begins with mild symptoms, with fevers, chills, vomiting and headaches. Some cases can then enter a second, more severe phase that can result in kidney or liver failure.
Ventura County Public Health recommends agriculture and berry harvesters regularly rinse any cuts with soap and water and cover them with bandages. They also recommend wearing waterproof clothing and protection while working outdoors, including gloves and long-sleeve shirts and pants.
While there is no evidence of spread to the larger community, according to the department, residents should wash hands frequently and work to control rodents around their property if possible.
Pet owners can consult a veterinarian about leptospirosis vaccinations and should keep pets away from ponds, lakes and other natural bodies of water.
Science
Political stress: Can you stay engaged without sacrificing your mental health?
It’s been two weeks since Donald Trump won the presidential election, but Stacey Lamirand’s brain hasn’t stopped churning.
“I still think about the election all the time,” said the 60-year-old Bay Area resident, who wanted a Kamala Harris victory so badly that she flew to Pennsylvania and knocked on voters’ doors in the final days of the campaign. “I honestly don’t know what to do about that.”
Neither do the psychologists and political scientists who have been tracking the country’s slide toward toxic levels of partisanship.
Fully 69% of U.S. adults found the presidential election a significant source of stress in their lives, the American Psychological Assn. said in its latest Stress in America report.
The distress was present across the political spectrum, with 80% of Republicans, 79% of Democrats and 73% of independents surveyed saying they were stressed about the country’s future.
That’s unhealthy for the body politic — and for voters themselves. Stress can cause muscle tension, headaches, sleep problems and loss of appetite. Chronic stress can inflict more serious damage to the immune system and make people more vulnerable to heart attacks, strokes, diabetes, infertility, clinical anxiety, depression and other ailments.
In most circumstances, the sound medical advice is to disengage from the source of stress, therapists said. But when stress is coming from politics, that prescription pits the health of the individual against the health of the nation.
“I’m worried about people totally withdrawing from politics because it’s unpleasant,” said Aaron Weinschenk, a political scientist at the University of Wisconsin–Green Bay who studies political behavior and elections. “We don’t want them to do that. But we also don’t want them to feel sick.”
Modern life is full of stressors of all kinds: paying bills, pleasing difficult bosses, getting along with frenemies, caring for children or aging parents (or both).
The stress that stems from politics isn’t fundamentally different from other kinds of stress. What’s unique about it is the way it encompasses and enhances other sources of stress, said Brett Ford, a social psychologist at the University of Toronto who studies the link between emotions and political engagement.
For instance, she said, elections have the potential to make everyday stressors like money and health concerns more difficult to manage as candidates debate policies that could raise the price of gas or cut off access to certain kinds of medical care.
Layered on top of that is the fact that political disagreements have morphed into moral conflicts that are perceived as pitting good against evil.
“When someone comes into power who is not on the same page as you morally, that can hit very deeply,” Ford said.
Partisanship and polarization have raised the stakes as well. Voters who feel a strong connection to a political party become more invested in its success. That can make a loss at the ballot box feel like a personal defeat, she said.
There’s also the fact that we have limited control over the outcome of an election. A patient with heart disease can improve their prognosis by taking medicine, changing their diet, getting more exercise or quitting smoking. But a person with political stress is largely at the mercy of others.
“Politics is many forms of stress all rolled into one,” Ford said.
Weinschenk observed this firsthand the day after the election.
“I could feel it when I went into my classroom,” said the professor, whose research has found that people with political anxiety aren’t necessarily anxious in general. “I have a student who’s transgender and a couple of students who are gay. Their emotional state was so closed down.”
That’s almost to be expected in a place like Wisconsin, whose swing-state status caused residents to be bombarded with political messages. The more campaign ads a person is exposed to, the greater the risk of being diagnosed with anxiety, depression or another psychological ailment, according to a 2022 study in the journal PLOS One.
Political messages seem designed to keep voters “emotionally on edge,” said Vaile Wright, a licensed psychologist in Villa Park, Ill., and a member of the APA’s Stress in America team.
“It encourages emotion to drive our decision-making behavior, as opposed to logic,” Wright said. “When we’re really emotionally stimulated, it makes it so much more challenging to have civil conversation. For politicians, I think that’s powerful, because emotions can be very easily manipulated.”
Making voters feel anxious is a tried-and-true way to grab their attention, said Christopher Ojeda, a political scientist at UC Merced who studies mental health and politics.
“Feelings of anxiety can be mobilizing, definitely,” he said. “That’s why politicians make fear appeals — they want people to get engaged.”
On the other hand, “feelings of depression are demobilizing and take you out of the political system,” said Ojeda, author of “The Sad Citizen: How Politics is Depressing and Why it Matters.”
“What [these feelings] can tell you is, ‘Things aren’t going the way I want them to. Maybe I need to step back,’” he said.
Genessa Krasnow has been seeing a lot of that since the election.
The Seattle entrepreneur, who also campaigned for Harris, said it grates on her to see people laughing in restaurants “as if nothing had happened.” At a recent book club meeting, her fellow group members were willing to let her vent about politics for five minutes, but they weren’t interested in discussing ways they could counteract the incoming president.
“They’re in a state of disengagement,” said Krasnow, who is 56. She, meanwhile, is looking for new ways to reach young voters.
“I am exhausted. I am so sad,” she said. “But I don’t believe that disengaging is the answer.”
That’s the fundamental trade-off, Ojeda said, and there’s no one-size-fits-all solution.
“Everyone has to make a decision about how much engagement they can tolerate without undermining their psychological well-being,” he said.
Lamirand took steps to protect her mental health by cutting social media ties with people whose values aren’t aligned with hers. But she will remain politically active and expects to volunteer for phone-banking duty soon.
“Doing something is the only thing that allows me to feel better,” Lamirand said. “It allows me to feel some level of control.”
Ideally, Ford said, people would not have to choose between being politically active and preserving their mental health. She is investigating ways to help people feel hopeful, inspired and compassionate about political challenges, since these emotions can motivate action without triggering stress and anxiety.
“We want to counteract this pattern where the more involved you are, the worse you are,” Ford said.
The benefits would be felt across the political spectrum. In the APA survey, similar shares of Democrats, Republicans and independents agreed with statements like, “It causes me stress that politicians aren’t talking about the things that are most important to me,” and, “The political climate has caused strain between my family members and me.”
“Both sides are very invested in this country, and that is a good thing,” Wright said. “Antipathy and hopelessness really doesn’t serve us in the long run.”
Science
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