Yo-yo dieting dangerous for women’s hearts, study says

— Yo-yo dieting may increase the risk for coronary heart disease and sudden cardiac death in post-menopausal women, according to a study presented to the American Heart Association on Tuesday.

Although previous research focused on the heart risks associated with obesity, study leader Dr. Somwail Rasla of Memorial Hospital of Rhode Island questioned whether women with normal weights could be putting their hearts in danger by on-and-off dieting.

There’s evidence that being overweight in midlife increases risk of dying from two types of heart disease, according to the heart association — coronary heart disease, in which blood vessels are blocked by fat and other material, or sudden cardiac death, where the heart’s electrical system suddenly stops working.

But it wasn’t clear whether losing or gaining weight in adulthood increased the risk of death from those diseases.

“We wanted to know if weight cycling is clinically significant,” Rasla said.

Does weight cycling effect our hearts?

To find the answer, researchers studied 153,063 post-menopausal women who self-reported their weights.

At the start of the study, women were asked to describe their weights as normal (with a body mass index less than 25), overweight (a BMI of 25 to 29.9) or obese (a BMI greater than 30). They also reported their adult weight histories, describing themselves as maintaining stable weight, steadily gaining weight, steadily losing weight or weight cycling (if they had lost and regained 10 pounds or more). Weight gained and lost during pregnancy didn’t count as weight cycling, Rasla said.

Researchers followed the outcome of their participants for more than 11 years, recording fatalities due to coronary heart disease and sudden cardiac death.

Over the course of the study, 2,526 coronary heart disease deaths and 83 sudden cardiac death deaths were recorded. Researchers categorized the deaths based on the women’s starting weights and their weight histories over time.

For overweight and obese women, weight cycling was not associated with the risk of heart disease-related deaths.

But the most surprising findings came from the group of normal-weight women who confessed to weight cycling. They were 3½ times more likely to have sudden cardiac death than women with stable weights. Additionally, yo-yo dieting in normal-weight women was associated with a 66% increased risk of coronary heart disease deaths, according to the research.

“Normal-weight women who said ‘yes’ to weight cycling when they were younger had an increased risk of sudden cardiac death and increased risk of coronary heart disease, which can lead to heart attacks and other serious issues,” Rasla said.

The frequency of weight cycling — how often the women had lost and regained 10 pounds or more — was also a risk factor. “The more cycling, the more hazardous (to their hearts),” Rasla explained.

The dangers of yo-yo dieting

Women are more likely to change their weight frequently: According to Rasla, 20% to 55% of the female population of the United States has admitted to weight cycling, while only 10% to 20% of men have. Though it’s a common issue, the clinical significance of weight cycling isn’t always agreed on.

“Some studies say weight cycling has no effects on health,” Rasla said. Others claim that it can cause cancer, diabetes and other illnesses.

According to Rasla, one reason weight cycling may be harmful is “overshoot theory”: When someone changes weight frequently, he explained, gaining weight increases health risk by raising blood pressure, cholesterol and body fat. When she loses the weight, these levels drop, but not all the way to her healthy baseline, because her “normal” state was overshot by the weight gain. If these cycles keep repeating, the woman’s health will decline, even if she appears “normal.”

“The appearance of health can be deceptive,” said Dr. Michael Miller, a professor of cardiovascular medicine at the University of Maryland School of Medicine who was not involved in the new research. “You can look and appear healthy, but you don’t know what your risk factors are.”

As a cardiologist, Miller often encounters the effects of weight cycling in his patients, particularly middle-age women. “Yo-yo dieting can result in fluid shifts and electrolyte changes, such as potassium, that can cause deadly heart arrhythmias in susceptible middle-aged women,” he said.

Men are also negatively affected by weight cycling, but Miller sees the condition “more in women than men.”

“Popular diets want you to lose weight quickly, often by reducing your caloric intake by 500 to 1,000 calories a day,” he said. When this happens, the dieter’s levels of electrolytes, calcium and magnesium are depleted, which can be very hazardous to the body. “You should never lose weight in a drastic fashion,” he said.

“Under normal conditions, we shouldn’t be putting on or losing weight,” Miller continued.

“If someone is a normal weight, keep it stable,” Rasla agreed.

If a patient wants to lose some weight, Miller warns not to lose more than a pound a week. Instead of restricting food, he suggests eating a healthy diet and increasing energy output, or physical exercise, by about 300 calories a day.

Dr. Naveed Sattar, a professor of metabolic medicine at the University of Glasgow who wasn’t involved in the study, emphasizes that weight loss is still a healthy choice for many people.

“This study does not change the fact that overall evidence shows the value of intentional weight loss where lifestyle changes lead to beneficial weight change,” Sattar said. “If we look beyond this study at the totality of evidence, it shows us that if women (or men) try to lose weight intentionally, then there is no evidence from trials that this does anything other than good, even if weight gain recurs.”

Outside factors?

Dr. Suzanne Steinbaum, director of Women’s Heart Health at Lenox Hill Hospital and a Heart Association spokeswoman, says the study “shows the real, true negative effects of what yo-yo dieting can do on our hearts, and this is very, very relevant and important for us to see and understand.” Steinbaum was not involved in the research.

However, she continued, “I don’t know how much emphasis we can put on this study, because it is an observational study” and is therefore not conclusive about the effects of yo-yo dieting.

“In observational studies, there are always factors that can’t be adjusted for,” such as pre-existing unhealthy habits, Miller said. These outside factors may have triggered the women’s heart conditions, he explained.

“This study has limitations,” Sattar agreed. “Women of normal weight are less likely to be intentionally losing weight than overweight women, so this weight loss in normal weight women is much more likely to be unintentional and could be due to illnesses, and the study cannot rule that out. So, weight cycling in normal weight women may be disguising some underlying illness, and these same illnesses may also in turn increase heart disease risks.”

Rasla also noted that the data collected for the study were self-reported, and the participants could have given biased answers. For future studies, he hopes to see participants’ weights monitored for better precision.

Miller is hopeful about the study results and future research on yo-yo dieting’s effects on heart health. “I think it’s a great start,” he said.

Skin patches may help kids’ peanut allergies, study says

Peanut allergies are among the most serious food allergies, requiring constant vigilance. In severe cases, exposure to even trace amounts of the nut can trigger a deadly reaction. But according to a new study published last week in the Journal of Allergy and Clinical Immunology, a tiny skin patch may help treat peanut allergies.

Over the course of a year, researchers from the Consortium of Food Allergy Research tested 74 peanut-allergic volunteers, ages 4 through 20, to see whether a daily Viaskin peanut patch could help raise their peanut threshold. The patch, called epicutaneous immunotherapy, released peanut proteins into the participants’ skin, building cellular tolerance to the nuts.

The results showed that participants who received higher doses of peanut protein in the patch were able to consume more peanuts after a year. The patch was the most effective on children ages 4 to 11 and significantly less effective on older participants, according to a statement from the National Institutes of Health, which funded the study through its National Institute of Allergy and Infectious Diseases.

The trial

The peanut patch trial was conducted at five research sites: Arkansas Children’s Hospital, the National Jewish Health Center in Denver, Johns Hopkins University, the Icahn School of Medicine at Mount Sinai and the University of North Carolina at Chapel Hill School of Medicine.

The newly published results were from the first year of the trial, but the researchers will continue monitoring the participants for a total of two and a half years.

To conduct the yearlong study, researchers divided participants into three groups: a placebo group that received patches with no peanut protein, a group given patches with 100 micrograms of peanut protein and one given patches with 250 micrograms of peanut protein. The 74 participants were randomly assigned to each group.

Before the trial began, researchers assessed each volunteer’s peanut allergy via an oral food challenge with food containing peanuts. The median amount of nuts tolerated, before having allergic symptoms was about one-seventh of a peanut, according to Dr. Stacie M. Jones, chief of allergy and immunology at Arkansas Children’s Hospital and the study lead.

After establishing an allergy baseline, the participants were given quarter-size patches on the insides of their upper arms for adolescents, or on their backs for younger kids.

The patches were administered daily for the 52-week period, but Jones said placement varied in order to allow any skin irritation to heal.

The risks of the peanut patch

One of the main concerns for researchers, as well as peanut-allergic volunteers, was whether the patch would trigger a harmful allergic reaction. Of the 74 participants, one teenager had to leave due to a patch reaction, according to Jones.

About 80% of the kids who used peanut patches (both low- and high-dose strength) had some reaction, Jones said, but they were mainly mild, like bumps and redness on the skin surrounding the patch.

Jones explained that the patches, which are manufactured by DBV Technologies, are coated with sub-clinical doses (meaning they have a very small potential of triggering allergic reaction) of raw peanut material. When peanut proteins are released into the skin, it starts an immune reaction in the cells, she said.

Importantly, she explained, the peanut proteins from the patch do not enter the bloodstream. After participants handled the patch, they were warned not to touch their eyes or mouths and to wash their hands immediately.

Results of the peanut patch trial

After a year of using the skin patches, the three groups were again assessed for peanut allergies. This time, many participants who had used peanut patches could tolerate more peanuts than those who used placebo patches.

Before the researchers began the trial, they set a goal of a tenfold increase in participants’ peanut threshold, meaning they could eat 10 times more peanuts at the end of the year, Jones said. And the treatment seemed to work for many low-dose and high-dose patch wearers, but not for everyone.

Forty-six percent of participants who had 100-microgram patches were able to raise their peanut threshold at least tenfold, as did 48% of the 250-microgram patch wearers. Only 12% of the placebo group met the tenfold goal.

In terms of peanuts, the kids who wore the low-dose patch were able to eat one-seventh more of a peanut, on average, than they could before. Kids with high-dose patches could eat an extra half of a peanut, on average. “It’s a moderate treatment response,” Jones said.

Children ages 4 to 11 showed the most improvement, Jones said, but kids 12 and older were less affected.

Not a license to eat

Dr. Jennifer Shih, an assistant professor at Emory University School of Medicine who specializes in pediatric allergies, said the peanut patch study is promising, but it doesn’t mean an end to peanut allergy problems.

“This (patch) is not so that somebody can eat a bunch of Reese’s for Halloween,” she said. Rather, those who use a peanut patch are “hopefully protected from accidental exposure” to peanuts.

From unclear food labels to large school cafeterias, it can be difficult to avoid peanuts. This can cause a lot of anxiety, particularly for severely allergic patients, Shih said. The patch’s protection — even if it increases someone’s tolerance just a couple of peanuts — could ease some anxiety both for allergic children and for their parents.

“To avoid potentially life-threatening allergic reactions, people with peanut allergy must be vigilant about the foods they eat and the environments they enter, which can be very stressful,” Dr. Anthony Fauci, director of the National Institute of Allergy and Infectious Diseases, said in the National Institutes of Health statement. “One goal of experimental approaches such as epicutaneous immunotherapy is to reduce this burden by training the immune system to tolerate enough peanut to protect against accidental ingestion or exposure.”

The patch may also ease anxiety because it’s not a shot like other allergy treatments. Since young children are especially afraid of needles, the fact that the patch appears to be most effective on kids ages 4 to 11 is exciting, Shih says.

Still, there are some concerns to consider. The study tested only kids with peanut allergies and no other medical issues, so there’s no way of knowing whether the patch can aggravate other problems, such as additional allergies, Shih said.

Problems may occur if patients didn’t use the patch as directed or if they forgot to put it on for a day. “They have to (use the patch) every day, or they might become intolerant,” Shih said. However, the study did prove successful in participant retention: Nearly 97% of participants applied the patch every day, according to Jones.

The results of the study were also “not 100%,” Shih said. Though about half of the participants succeeded in raising their peanut threshold with the patch, that still wasn’t the majority of the group.

“When I saw this study, I was excited because it is positive, and it can give hope,” Shih said. “Still, it’s not something we’ll run off to the store to get right away.”