February 15, 2024 lfbswa

How do trees and green spaces enhance our health?

Green, leafy trees with brown trunks in a park and rays of golden sunlight pouring down through the leaves

Trees enhance life in a multitude of ways. They combat climate change by reducing greenhouse gases in the atmosphere. They muffle sound pollution and reduce air pollution, drawing in carbon dioxide and releasing oxygen. When rain pours from the skies, trees decrease stormwater runoff, preventing flooding and soil erosion. They also provide valuable habitats to support biodiversity in insects, birds, and other animals, and microorganisms. The list goes on.

Equally important is accumulating evidence that simply spending time around trees and green spaces uplifts our health and mood. Below are a few of the biggest benefits we reap.

Keeping it cool: Trees help prevent heat-related illness

Climate change is causing rising temperatures and more heat waves across the US. These effects are worse for those who live in neighborhoods known as urban heat islands, where asphalt and concrete soak up heat during the day and continue to radiate it at night. Temperatures can reach 7° F hotter than suburban, rural, or simply wealthier and leafier neighborhoods.

Trees and their leafy canopy provide shade that helps to prevent urban heat islands. What does that mean for individuals? It translates to fewer heat-related health illnesses, which strike outdoor workers and younger, older, and medically vulnerable people more often. A study published in The Lancet calculated that increasing tree canopy to 30% coverage in 93 European cities could prevent an estimated four in 10 premature heat-related deaths in adults in those cities.

How trees help children: Better mood, behavior, attention, and more

Spending more time in nature has been linked with better health outcomes like lower blood pressure, better sleep, and improvement in many chronic conditions in adults. These findings are prompting a growing interest in forest therapy, a guided outdoor healing practice that leads to overall improved well-being. But what’s also remarkable are the varied benefits of trees and nature for children.

One study of children 4 to 6 years old found that those who lived close to green space demonstrated less hyperactive behavior and scored more highly on attention and visual memory testing measures compared with children who did not.

Just seeing trees can have mental health benefits. In Michigan, a study of children between the ages of 7 and 9 demonstrated that students who could see trees from their school windows had fewer behavioral problems than those with limited views.

In Finland, researchers modified daycare outdoor playscape environments to mimic the forest undergrowth. These daycares were compared to control standard daycares and nature-oriented daycares where children made daily visits to nearby forests. At the end of 28 days, the children in the daycares with modified forest undergrowth playscapes harbored a healthier microbiome and had improved markers of their immune systems as compared to their counterparts.

How green space helps communities

Having green space in neighborhoods also does a lot to enrich the well-being of communities. A randomized trial in a US city planted and maintained grass and trees in previously vacant lots. Researchers then compared these green spaces to lots that were left alone.

In neighborhoods below the poverty line, there was a reduction in crime for areas with greened lots compared to untouched vacant lots. Meanwhile, residents who lived near lots that were greened reported feeling safer and increased their use of the outside space for relaxing and socializing.

How can you help?

Unfortunately, urban tree canopy cover has been declining over the years. To counter this decline, many towns and nonprofit organizations have programs that provide trees for planting.

A few examples in Massachusetts are Canopy Crew in Cambridge and Speak for the Trees in Boston. (Speak for the Trees also offers helpful information on selecting and caring for trees). Neighborhood Forest provides trees for schools and other youth organizations across the US. Look for a program near you!

Planting trees native to your region will better suit the local conditions, wildlife, and ecosystem. Contact your regional Native Plant Society for more information and guidance. If you are worried about seasonal allergies from tree pollen, many tree organizations or certified arborists can give you guidance on the best native tree selections.

If planting trees is not for you but you are interested in contributing to the mission, consider donating to organizations that support reforestation, like The Canopy Project and the Arbor Day Foundation.

About the Author

photo of Wynne Armand, MD

Wynne Armand, MD, Contributor

Dr. Wynne Armand is a physician at Massachusetts General Hospital (MGH), where she provides primary care; an assistant professor in medicine at Harvard Medical School; and associate director of the MGH Center for the Environment and … See Full Bio View all posts by Wynne Armand, MD

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February 13, 2024 lfbswa

Concussion in children: What to know and do

Illustration of a tiny person with black hair putting two crossed bandages on a large, pink injured brain; concept is concussion

Concussion is one of the most common injuries to the brain, affecting about two million children and teens every year. It is a particular kind of injury that happens when a blow to the head or somewhere else on the body makes the brain move back and forth within the skull.

It’s possible to get a concussion after what might seem like a minor injury, like a forceful push from behind, or a collision between two players in a football or soccer game.

What are the signs and symptoms of concussion?

Because the injury may not seem that significant from the outside, it’s important to know the symptoms of a concussion. There are many different possible symptoms, including

  • passing out (this could be a sign of a more serious brain injury)
  • headache
  • dizziness
  • changes in vision
  • feeling bothered by light or noise
  • confusion or feeling disoriented
  • memory problems (such as difficulty remembering details of the injury) or difficulty concentrating
  • balance or coordination problems
  • mood changes.

Some of these are visible to others and some are felt by the person with the concussion. That’s why it’s important to know the signs and to ask all the right questions of a child who has had an injury.

Sometimes the symptoms might not be apparent right away, but show up in the days following the injury. The CDC’s Heads Up website has lots of great information about how to recognize a concussion.

How can further harm to the brain be avoided?

The main reason it’s important to recognize a possible concussion early is that the worst thing you can do after getting a concussion is get another one. The brain is vulnerable after a concussion; if it is injured again, the symptoms can be longer lasting — or even permanent, as in cases of chronic traumatic encephalopathy (CTE), a condition that has been seen in football players and others who have repeated head injuries.

If there is a chance that a child has had a concussion during a sports competition, they must stop playing — and get medical attention. It’s important to get medical attention any time there is concern about a possible concussion, both to be sure there isn’t a more serious brain injury, and to do a good assessment of the symptoms, so that they can be monitored over time. There are some screening questionnaires that are used by doctors that can be used again in the days and weeks after the concussion to see how the child is improving.

What helps children recover after a concussion?

Experts have struggled with figuring out how to protect the brain after a concussion. For a long time, the recommendation was to rest and do very little at all. This meant not doing any exercise, not going to school, not even reading or watching television. As symptoms improved, the restrictions were lifted gradually.

Over time, though, research showed that not only was this much rest not necessary, it was counterproductive. It turns out that getting kids back into their daily lives, and back into being active, is safe and leads to quicker recovery. Experts still recommend rest and then moving gradually back into activities, but the guidelines are no longer as strict as they once were.

One important note: A medical professional should guide decisions to move from rest to light activity, and then gradually from there to moderate and then regular activities based on how the child is doing. This step-by-step process may extend for days, weeks, or longer, depending on what the child needs. Parents, coaches, and schools can help support a child or teen as they return to school and return to activities and sports.

Some children will be able to get back into regular activities quickly. But for others it can take weeks or even months. Schools and sports trainers should work with children to support them in their recovery. Some children develop post-concussive syndromes with headache, fatigue, and other symptoms. This is rare but can be very disabling.

How can parents help prevent concussions?

It's not always possible to prevent concussions, but there are things that parents can do:

  • Be sure that children use seat belts and other appropriate restraints in the car.
  • Have clear safety rules and supervise children when they are playing, especially if they are riding bikes or climbing in trees or on play structures.
  • Since at least half of concussions happen during sports, it’s important that teams and coaches follow safety rules. Coaches should teach techniques and skills to avoid dangerous collisions and other injuries. Talk to your child’s coaches about what they are doing to keep players safe. While helmets can prevent many head injuries, they don’t prevent concussions.

About the Author

photo of Claire McCarthy, MD

Claire McCarthy, MD, Senior Faculty Editor, Harvard Health Publishing

Claire McCarthy, MD, is a primary care pediatrician at Boston Children’s Hospital, and an assistant professor of pediatrics at Harvard Medical School. In addition to being a senior faculty editor for Harvard Health Publishing, Dr. McCarthy … See Full Bio View all posts by Claire McCarthy, MD

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February 2, 2024 lfbswa

How healthy is sugar alcohol?

A blue background sprinkled with white sugar substitute crystals with the words sugar free written; concept is sugar alcohols and artficial sweeteners

If you are trying to cut back on added sugar — and you should, because excess sugar increases risks for obesity, diabetes, and heart disease — you might be tempted by products advertised as low sugar, no sugar, or sugar-free.

Many contain familiar low-calorie sugar substitutes like aspartame or sucralose instead of sugar. And as you’re reading labels, you also may run across another ingredient: sugar alcohol, which is used in products like sugar-free cookies, candies, ice cream, beverages, and chewing gums. Are any of these sweeteners a better choice nutritionally? Dr. Frank Hu, professor of nutrition and epidemiology with the Harvard T.H. Chan School of Public Health, weighs in below.

Are low-calorie or no-calorie sweeteners any healthier than natural sugar?

Also known as artificial sweeteners or sugar substitutes, the list of low-calorie and no-calorie sweeteners you may see on product nutrition labels includes acesulfame-K, saccharin, sucralose, neotame, and advantame. These have a higher sweetness intensity per gram than natural sugar.

So far research on them is mixed, although some observational studies have found that beverages containing low-calorie sweeteners are associated with a higher risk for diabetes and weight gain.

What exactly are sugar alcohols and how can you spot them?

Sugar alcohols may have the most misleading name, as they are neither sugar nor alcohol, according to Dr. Hu. “They are a type of carbohydrate derived from fruits and vegetables, although most commercial sugar alcohols are synthetically produced.”

You can usually spot many sugar alcohols on ingredient lists by “-ol” at the ends of their names. Examples include sorbitol, xylitol, lactitol, mannitol, erythritol, and maltitol.

Are sugar alcohols any healthier than other sugar substitutes or natural sugar?

Here is a look at the pros and cons.

The upside of sugar alcohols

Sugar alcohols reside in the sweet spot between natural sugar and low-calorie sweeteners. They are not as overly sweet as sweeteners and don’t add too many extra calories like sugar.

“Sugar alcohols are about 40% to 80% as sweet as natural sugar, whereas artificial sweeteners like aspartame are about 200 times sweeter,” says Dr. Hu. “And they have about 25% to 75% fewer calories per gram than sugar.”

Another upside of sugar alcohols is that they break down slowly in the gut. Hence, your body only absorbs part of their overall carbohydrates. “This keeps your blood sugar and insulin levels from spiking as they do with sugar,” says Dr. Hu. “That makes them a useful sugar substitute for people with diabetes.”

The downside of sugar alcohols

The main downside to sugar alcohols is this: when taken in high amounts they can cause gastrointestinal (GI) problems, such as abdominal pain, diarrhea, or loose stools.

Because sugar alcohols are slowly digested, they have more time to feed bacteria in the gut, which can lead to fermentation and produce excess gas. Their slow digestion also can pull extra water into the colon and cause a laxative effect.

People’s tolerance for sugar alcohols depends on many factors, including body weight, health conditions, and the amount and types of sugar alcohols. “Individual differences in digestion and metabolism, gut microbiome composition, and dietary habits can also make a difference,” says Dr. Hu. “For these reasons, we recommend introducing sugar alcohols into your diet gradually and observing how your body responds.”

For people who experience GI symptoms caused by sugar alcohols, Dr. Hu says cutting back on the amount of foods and drinks made with them often can correct the problem. “Sugar alcohols are commonly found in sugar-free or low-carb products, so pay attention to food labels” he says. “Because different sugar alcohols can have different effects, it might be useful to identify specific types of sugar alcohols that cause GI side effects.”

Do sugar alcohols have health risks?

Possible long-term health risks of sugar alcohol are still being explored. A 2023 observational study found a link between using erythritol as an added sweetener and cardiovascular disease events, such as stroke and heart attack, in people with heart disease or who had risk factors like diabetes and high blood pressure. However, these findings have not been confirmed in subsequent studies.

“Sugar alcohols offer a healthier alternative to sugar because of their lower calorie content and reduced glycemic response, which is the effect food has on blood sugar levels,” says Dr. Hu. “But they also have potential drawbacks, especially for those with sensitive digestive systems, so it’s best to consume them in moderation as part of an overall healthy eating pattern.”

About the Author

photo of Matthew Solan

Matthew Solan, Executive Editor, Harvard Men's Health Watch

Matthew Solan is the executive editor of Harvard Men’s Health Watch. He previously served as executive editor for UCLA Health’s Healthy Years and as a contributor to Duke Medicine’s Health News and Weill Cornell Medical College’s … See Full Bio View all posts by Matthew Solan

About the Reviewer

photo of Howard E. LeWine, MD

Howard E. LeWine, MD, Chief Medical Editor, Harvard Health Publishing

Dr. Howard LeWine is a practicing internist at Brigham and Women’s Hospital in Boston, Chief Medical Editor at Harvard Health Publishing, and editor in chief of Harvard Men’s Health Watch. See Full Bio View all posts by Howard E. LeWine, MD

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