Here Comes the Sun
Should I use sun-block?
Singapore’s UV index hit extreme levels in March this year, prompting cautionary advice from authorities. In a recent episode of Talking Point, Diana Ser tells us all about the dangers of UV rays and examines if UV products do keep us safe.
Diana Ser, 46, media personality and mother of three kids aged 12, 10 and seven, sums up her skincare credo with two words: Hydration and sunscreen. “No matter how busy I am, I reapply [sunblock] with an SPF 50 mist every two to three hours to protect my skin from harmful UV rays and the damage they inflict," said Ser.
Everyone knows that, on the one hand, sun exposure helps your body make vitamin D. But on the other, it can cause skin cancer.
The most common form of skin cancer by far are basal-cell carcinomas and squamous-cell carcinomas, which are almost never fatal. In fact, says dermatologist at the University of Edinburgh Richard Weller, “When I diagnose a basal-cell skin cancer in a patient, the first thing I say is congratulations, because you’re walking out of my office with a longer life expectancy than when you walked in.” That’s probably because people who get carcinomas, which are strongly linked to sun exposure, tend to be healthy types that are outside getting plenty of exercise and sunlight.
Melanoma, the deadly type of skin cancer, is much rarer, accounting for only 1 to 3 percent of new skin cancers. And perplexingly, outdoor workers have half the melanoma rate of indoor workers. And there’s evidence that long-term sun exposure associates with less melanoma.
In this article:
Is sun exposure that bad for health?
Taking Vitamin D supplements: Good or Bad?
Sun exposure and blood pressure
Sun exposure has been shown to have a notable impact on blood pressure, with multiple studies suggesting beneficial effects. Here are some key findings on the relationship between sun exposure and blood pressure:
Reduction in Blood Pressure: Recent studies indicate that exposure to sunlight can lead to a reduction in blood pressure. This is primarily due to the production of nitric oxide, a molecule that is released into the blood vessels when the skin is exposed to UV rays. Nitric oxide helps to relax and widen blood vessels, which in turn lowers blood pressure .
Short-Term Effects: Research has demonstrated that even short-term exposure to sunlight can have immediate effects on blood pressure. For example, a study found that short-term sunlight exposure resulted in decreased systolic blood pressure (SBP) and diastolic blood pressure (DBP). Specifically, the average SBP decreased from 132.6 mm Hg to 129.3 mm Hg, and DBP decreased from 77.6 mm Hg to 75.8 mm Hg .
Long-Term Health Benefits: Regular exposure to sunlight may contribute to long-term cardiovascular health benefits. Lower blood pressure reduces the risk of cardiovascular events such as heart attacks and strokes. It is suggested that populations with higher exposure to sunlight have lower incidences of hypertension-related complications .
Seasonal Variations: Blood pressure tends to be lower in the summer and higher in the winter, which may be partly due to varying levels of sunlight exposure. The body produces more vitamin D in response to sunlight during the summer months, which also plays a role in cardiovascular health .
Safe Sun Exposure: While moderate sun exposure can be beneficial, it is essential to balance it with skin cancer risks. Using sun protection and avoiding peak sun hours can help mitigate these risks while still reaping the benefits of sunlight for blood pressure control.
Sun exposure and bone health
Sun exposure plays a crucial role in bone health primarily due to its role in vitamin D production. Here's how sun exposure affects bone health:
1. Vitamin D Synthesis: Sun exposure is the primary source of vitamin D for most people. When the skin is exposed to sunlight, it produces vitamin D, which is essential for calcium absorption and bone mineralization. Adequate vitamin D levels help prevent conditions like osteoporosis and osteomalacia.
2. Bone Density: Research has shown that regular sun exposure, combined with physical activity such as walking, can improve bone mineral density (BMD). This is especially beneficial for older adults who are at risk of osteopenia or osteoporosis. Sun exposure stimulates the production of osteoblasts, cells responsible for bone formation.
3. Balance and Fall Prevention: In addition to improving BMD, sun exposure combined with physical activity like brisk walking can enhance dynamic and static balance, reducing the risk of falls and fractures in the elderly population.
4. Guidelines for Safe Exposure: Guidelines typically recommend about 5-10 minutes of sun exposure to the arms, legs, or face, a few times per week, to ensure adequate vitamin D production without increasing the risk of skin cancer. This amount of exposure is usually sufficient for most people to maintain healthy vitamin D levels.
Sun exposure and immunity
Sun exposure has significant implications for immunity, primarily through its effects on vitamin D production and other mechanisms. Here's how sun exposure influences the immune system:
1. Vitamin D Synthesis: Sunlight is crucial for the synthesis of vitamin D in the skin. Vitamin D plays a pivotal role in modulating the immune system. It enhances the pathogen-fighting effects of monocytes and macrophages, which are essential components of the immune response against infections.
2. Regulation of Immune Response: Sunlight exposure can influence the immune response in various ways. UV radiation can induce immunosuppression initially, but controlled exposure also enhances immune function over time. This dual effect highlights the importance of balanced sun exposure for immune health.
3. Skin's Role in Immunity: The skin acts as a barrier against pathogens, and UV radiation can affect immune cells within the skin itself. This interaction between sunlight and skin immune cells plays a role in both protecting against infections and managing inflammatory responses.
4. Overall Health Benefits: Beyond vitamin D, sunlight exposure has been associated with improved mood and overall well-being, which can indirectly support immune function by reducing stress and enhancing quality of life.
5. Balancing Sun Exposure: While moderate sun exposure can boost immunity, excessive exposure can lead to sunburn and potentially suppress immune responses temporarily. It's essential to practice safe sun habits, including using sunscreen and avoiding prolonged exposure during peak UV hours.
Vitamin D supplementation
In spite of the wide ranging benefits of sun exposure and the fact that skin cancer kills surprisingly few people: less than 3 per 100,000 in the U.S. each year, the American Academy of Dermatology (AAD) continues to take a zero-tolerance stance on sun exposure and advices everyone to protect their skin from the sun every day, “even when it’s cloudy.”
By putting on sunscreen, you are blocking your skin’s ability to manufacture vitamin D. But that’s OK, according to the AAD. You can always compensate with vitamin D pills.
How effective is vitamin D supplementation?
Vitamin D supplementation has failed spectacularly in clinical trials. Five years ago, researchers were already warning that it showed zero benefit, and the evidence has only grown stronger. In November, one of the largest and most rigorous trials of the vitamin ever conducted—in which 25,871 participants received high doses for five years—found no impact on cancer, heart disease, or stroke.
People with low levels of vitamin D in their blood have significantly higher rates of virtually every disease and disorder you can think of: cancer, diabetes, obesity, osteoporosis, heart attack, stroke, depression, cognitive impairment, autoimmune conditions, and more.
Reference:
The Age Beauty Series: How to get the best skin in your 40s
Is Sunscreen the New Margarine?
Can Exposure to the Sun Affect Your Blood Pressure? - Flushing Hospital discusses the relationship between sun exposure and blood pressure, highlighting the role of nitric oxide.
Could sunshine lower blood pressure? Study offers enlightenment - The American Heart Association explores the potential of sunlight exposure to lower blood pressure based on a large study.
Effect of Short-Term Sunlight Exposure on Blood Pressure - A detailed study published in the journal "Cardiorenal Medicine" examines the effects of short-term sunlight exposure on blood pressure.
Associations between Physical Activity, Sunshine Duration - This article explores the relationship between physical activity, sun exposure, and vitamin D synthesis, emphasizing their impact on bone health.
Sunlight and vitamin D for bone health and prevention - A study by Holick discusses sensible sun exposure recommendations and dietary factors for optimizing bone health through vitamin D synthesis.
Effects of walking and sun exposure on bone density - This research article examines how walking and sun exposure can positively influence bone mineral density and balance in elderly individuals with osteopenia.
Sunbathing Can Boost Your Body's Immune System - This article discusses how sunlight exposure can enhance the immune system by promoting vitamin D synthesis and its implications for overall health.
Sunlight Effects on Immune System: Is There Something - A scholarly article that explores the complex interactions between sunlight exposure and the immune system, including UV-induced immunosuppression and long-term immune benefits.
Sunlight and Your Health - WebMD provides an overview of sunlight's effects on health, including its impact on immune function and considerations for safe sun exposure practices.