Squirrels that strongly favour their left or right side are less good at learning, new research suggests.

Grapefruit looks sweet and friendly, but you might have heard it possesses powers far beyond those of ordinary produce.

Some of that reputation is fact, and some is myth.

Facts first: According to the US Department of Agriculture, half a medium grapefruit has only 41 calories and nearly half a day’s recommended supply of vitamin C.

“In addition, it’s a reasonable source of potassium,” which is important for maintaining healthy blood pressure, said Karen Collins, a registered dietitian in western New York who specialises in cancer prevention and heart health.

Natural plant compounds

Grapefruit also is laden with natural plant compounds called phytochemicals, specifically flavonoids, which studies show can help fight stroke and heart disease. Pink and red grapefruit are good sources of beta carotene (a source of vitamin A) and lycopene, an antioxidant “cousin” to beta carotene that has been linked to lower stroke risk. One cup of red or pink grapefruit sections has as much lycopene as a medium 4-ounce tomato.

That’s all good. But grapefruit’s reputation for interfering with some medications is well-deserved.

It particularly affects certain anti-cholesterol statin drugs, as well as some medicines used to treat high blood pressure, irregular heartbeats and even allergies. Grapefruit and grapefruit juice can cause too much or too little of a drug to stay in the body. Too much drug increases the risk of side effects; too little means the drug may not work as well.

If you enjoy grapefruit or grapefruit juice and take such medications, there’s no need to panic, Collins said. But talk with your pharmacist or health care provider to clarify what’s safe. They might be able to switch your prescription to something unaffected by grapefruit, or even advise you to simply watch the timing of when you eat it.

Relatively few calories

In the past, grapefruit has been the very symbol of a “diet” food. Here’s where its reputation drifts into the realm of fable.

“The things that are not true are that grapefruit has some kind of magical power, or contains some kind of fat-burning enzyme, that you’re going to eat it and burn calories while you’re sleeping,” Collins said. Studies have found grapefruit provides no special boost to weight loss.

Even so, grapefruit’s tartness encourages people not to gulp it in a rush but to slow down, letting them feel full with relatively few calories, “and that is exactly an approach that research does support as the kind of eating pattern that helps people reach and maintain a healthy weight,” Collins said.

The classic way to enjoy grapefruit – splitting it and eating with a spoon – is OK, she said. (Be sure to rinse it before you cut: Otherwise, the knife might push bacteria on the skin through the entire fruit.)

But if you peel it like an orange and eat it by the section, you get added benefits from the membranes.

“Those membranes are rich in a type of dietary fibre called pectin, which is what we would call a viscous fibre,” Collins said. “And that is the type of fibre that can help lower (bad) LDL cholesterol and seems to be what they call a prebiotic that helps to nurture the healthy bacteria in our gut.”

For the best flavour, don’t chill it.

“It’s actually recommended that if you’re going to be eating grapefruit within the week to just store it at room temperature,” she said. It can keep for several weeks in the refrigerator, but it will taste better if you let it return to room temperature before serving.

‘A drop in the bucket’

She recommends trying it in a salsa, with chopped bell peppers and cilantro. “That adds a really nice, very crisp and refreshing kind of flavour like, say, on fish.” She also thinks the sections work great on a green salad. “You can combine it with avocado, and that’s kind of a classic.”

And if you’re in the habit of taking it with a sprinkling of salt or sugar?

First, she suggests, try it plain. “The grapefruit of today is really not necessarily the grapefruit of 30 years ago, and many of them don’t have as bitter a taste.”

Although most Americans already consume too much sodium and sugar, a tiny sprinkle of salt on half a grapefruit or a bit of brown sugar on a slice you stick under the broiler is “a drop in the bucket” compared with other choices you could make, Collins said.

“If you’re saying a quarter of a teaspoon of sugar makes it so you enjoy that grapefruit compared to a doughnut that has eight teaspoons of sugar in it, I would take the grapefruit.”

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Changes to smear tests will mean more HPV diagnoses but there is concern over myths about the virus.

Think the average human body temperature is 37°C or 98.6°F?

Not anymore, new research suggests.

Cooling down

“Our temperature’s not what people think it is,” said senior study author Dr Julie Parsonnet, a professor of medicine, health research and policy at Stanford University. “What everybody grew up learning, which is that our normal temperature is 98.6, is wrong.”

That standard was established in 1851, but a number of modern studies have suggested that it’s now too high. For example, a recent study found that the average body temperature of 25 000 British people was 97.9 °F (36.6 °C).

In the latest study, Parsonnet and colleagues analysed more than 677 000 body temperature measurements collected in the United States between 1862 and 2017.

The results showed that the body temperature of men born in the 2000s is, on average, almost 1.1 F lower than that of men born in the early 1800s. Meanwhile, the body temperature of women born in the 2000s is, on average, nearly 0.6 F lower than that of women born in the 1890s.

That translates into a body temperature decrease of 0.05 F every decade, according to the study published in the journal eLife.

One possible reason for the decrease in average body temperature in the United States could be a reduction in metabolic rate – the amount of energy that people burn – that may be due to a population-wide decline in inflammation.

More comfortable homes

“Inflammation produces all sorts of proteins and cytokines that rev up your metabolism and raise your temperature,” Parsonnet said in a Stanford news release.

She noted that over the past 200 years there have been dramatic improvements in public health due to advances in medical care, better hygiene, greater access to food and improved standards of living.

It’s also possible that more comfortable homes have contributed to the decline in average body temperature. Homes in the 19th century had uneven heating and no cooling, but central heating and air conditioning are now commonplace.

That means people don’t have to expend as much energy to maintain a constant body temperature.

“Physiologically, we’re just different from what we were in the past,” Parsonnet explained. “The environment that we’re living in has changed, including the temperature in our homes, our contact with microorganisms and the food that we have access to… We’re actually changing physiologically.”

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As kids head back to school, it’s important for parents to keep potential asthma and allergy challenges in mind.

“In the autumn, allergists see an increase in kids’ visits for allergies and asthma because of a combination of factors,” said Dr Todd Mahr, president of the American College of Allergy, Asthma and Immunology (ACAAI). “And hospitals see what’s known as the ‘September Spike’ because kids who have been off asthma controller medications for the summer start experiencing flare-ups in the fall.”

Allergy action plan

As a new school year begins, kids are exposed to allergens in the classroom, on playing fields and in the cafeteria that many probably haven’t run into all summer, he said in an ACAAI news release. On top of that, it’s ragweed season – a terrible time of year for kids who are allergic.

Mahr suggests parents meet with their child’s allergist this month to create an allergy action plan.

Parents should also try to identify potential asthma and allergy triggers that their children may encounter at school. These may include chemical compounds from new carpeting, pollen drifting into classrooms through open windows, or mould in bathrooms.

Parents should discuss potential triggers with teachers and school administrators to help ease symptoms.

Children with asthma or allergies should still be able to play any sport as long as they follow their allergist’s advice, according to the ACAAI.

Set up action plan

While physical activity can cause airways to constrict, if your child’s asthma is under control, he or she should be able to participate. Make sure coaches and physical education teachers know what to do if a problem arises.

If your child has a food allergy, make sure the school is fully informed. Work with your allergist and school staff to develop an action plan that lists foods your child is allergic to, treatment procedures and emergency contact information, the ACAAI advised.

Be sure your child understands what to do if he or she suffers an allergy or asthma emergency at school. They should carry and know how to use asthma and anaphylaxis medications, and school staff also should know how to administer them.

Amid the highest recorded pollen counts in history, Health24 will be bringing you exclusive pollen count updates courtesy of the UCT Lung Institute’s Allergy and Immunology Unit.

As the pollen problem worsens, precise and expanded monitoring becomes even more essential. And here’s how you can help.

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E-cigarettes are not a safer alternative to tobacco as far as strokes are concerned, according to a new study.

Young adults who use tobacco and e-cigarettes are nearly twice as likely to have a stroke as those who smoke only traditional cigarettes and almost three times as likely as nonsmokers, researchers say.

Risk doesn’t change

“While we already know that combustible cigarette use is one of the most important risk factors for stroke, [dual use] of e-cigarettes could potentially have an additive effect that may lead to stroke at a younger age,” said lead author Dr Tarang Parekh, a researcher at George Mason University in Fairfax, Virginia.

“In terms of a healthy alternative, if smokers were to switch to an e-cigarette, stroke risk does not change,” he added.

The study is one of the first aimed at gauging the potential stroke risk associated with use of e-cigarettes, said Dr Larry Goldstein, chairman of neurology at the University of Kentucky in Lexington. He reviewed the findings.

Because e-cigarettes are relatively new, Goldstein said it’s not surprising that the effect of their sole use on stroke risk is not yet apparent.

“But in no way should this be considered reassuring, as the impact on stroke risk may require longer periods of exposure and because of the study design, there are likely other unmeasured factors that could not be addressed that could affect risk,” Goldstein added.

Most concerning, he said, is that nearly 70% of sole e-cigarette users studied were 18 to 24 years old.

Risk among regular smokers

“This underscores the importance of restricting access to that population and removing incentives that could attract new users in this age group, such as flavoured products,” Goldstein said.

Also concerning is the increased risk among those who both vape and smoke regular cigarettes, as well as the risk among traditional smokers who switch to e-cigarettes, Goldstein said.

“Studies assessing the stroke, cardiovascular and other health risks of e-cigarettes and vaping are just beginning, and the long-term effects of exposure are largely unknown,” he said. “The relative lack of data should not be viewed as evidence of safety.”

For the study, Parekh and his team collected data on nearly 162,000 people between 18 and 44 who took part in a nationwide government health survey in 2016 and 2017.

Besides smoking, researchers took into account factors such as how often people used e-cigarettes and tobacco cigarettes and if they had high blood pressure, diabetes or high cholesterol. They also considered weight, physical activity and alcohol use.

They found that people who used e-cigarettes, tobacco cigarettes or both were more likely to be college dropouts or have only a high-school diploma. They were also more likely to be single, obese and binge drinkers.

Best strategy is quitting altogether

Stanton Glantz, director of the Center for Tobacco Control, Research and Education at the University of California, San Francisco, said most people don’t give up tobacco cigarettes for vaping. They’re likely to use both, which boosts their risk for both strokes and heart attacks.

Some proponents of vaping suggest that if people had used e-cigarettes all along instead of tobacco, there would have been fewer strokes and heart attacks, he said.

“But that’s not what the world is,” Glantz said. “The world is smoking tobacco and adding e-cigarettes. Long-term, they’re worse off than if they switch and no better off than if they use both.”

The best strategy for your health is to not smoke or vape, Glantz said.

The report was published in the American Journal of Preventive Medicine.

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The top number on a blood pressure test is widely viewed as the best gauge of a person’s overall risk for heart disease. But the bottom number could be important when it comes to evaluating the chance of a person having scars on their brain that could be an indicator for dementia, stroke or falls.

Researchers in a new study looked at the link between blood pressure scores and the number and location of these brain scars, called white matter lesions. In 1 205 women and men who were 50 and older – two-thirds of whom were Hispanic – the investigators found those with the lowest diastolic blood pressure (the bottom number) had fewer white matter lesions on MRI scans than those with higher diastolic blood pressure.

Smaller white matter lesions

Michelle R. Caunca, a medical student at the University of Miami Miller School of Medicine who led the study, said the team had expected to find systolic blood pressure (the top number) was associated with white matter lesions. Other studies have shown people with high systolic blood pressure are more likely to have the narrowed arteries that cause these lesions, she said.

Yet the new study, published in the journal Stroke, found people with diastolic blood pressure lower than 80 had smaller white matter lesions in three regions of the brain seen on MRI compared to people with diastolic blood pressure over 90.

“Different regions are supplied by different vessels, and certain (diseases) affect certain regions in different ways,” said Caunca. “Looking at different regions allows us to explore, in an indirect way” how blood pressure might affect the brain’s blood vessels.

“This focus on distinct regions is a new contribution to the literature,” said Dr Rebecca Gottesman, a professor of neurology and epidemiology at Johns Hopkins University in Baltimore who was not involved with the research.

“The specific relationship with periventricular (region) white matter lesions is important because these lesions tend to be more strongly associated with cognitive problems,” she said.

Systolic blood pressure indicates how much pressure a person’s blood exerts against the artery walls when their heart beats. Diastolic blood pressure indicates how much pressure a person’s blood exerts against the artery walls while their heart rests between beats.

The best treatment for you

People with a diastolic blood pressure reading of 80 or higher are considered to have high blood pressure, according to guidelines from the American College of Cardiology and American Heart Association.

White matter is composed of nerve fibres that transmit messages to and from the brain that help guide muscle movement, sensation and thinking. Lesions can block these messages, increasing the risk for falls. These lesions also increase a person’s risk of having a stroke or developing problems with thinking and memory.

By age 60, between 10% and 20% of people have white matter lesions, according to an AHA scientific statement about silent cerebrovascular disease. They are seen in most adults over age 90.

Caunca said although the association with diastolic blood pressure was not expected, it was consistent with other studies.

Gottesman said the new study “provides further evidence that it is important to know your blood pressure and talk to your doctor about the best treatment for you.”

It also shows, she said, “the importance of the diastolic blood pressure, which is less typically considered when decisions are being made about treating patients with hypertension.”

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