Monthly Archives: June 2017

Why does hair turn gray?

As you look in the mirror in the morning, you see that inevitable fate has struck: your first gray hair! Whether you are in your 20s or your 50s, gray hair catches up with all of us eventually.

During hair growth, melanocytes make pigment and pass it to hair progenitor cells at the base of the hair follicle. These cells, in turn, transform into the various components of the growing hair.

When our hair grows, pigments are continuously being incorporated, which results in our unique hair color. The cells responsible for this process are the pigment-producing melanocytes at the base of the hair follicle.

In normal hair growth, the follicle produces hair at a rate of around 1 centimeter per month for several years.

But all the cells in our body become increasingly damaged during our lifetime, and these melanocytes are eventually lost. When all the melanocytes are lost in a particular hair follicle, the next hair that grows will be gray or white.

The biology of hair growth is rather complex, with a multitude of specialized cells involved in hair follicle structure and function. Scientists continue to unravel the process of human hair growth and pigmentation.

What controls pigmentation?

Humans have two different types of pigment. Eumelanin is responsible for black and brown colors, while pheomelanin is responsible for orange and yellow.

Genes determine the mixture of pigments that each individual produces, which is why hair color is often similar within families.

The exact mechanisms that control pigmentation are not yet clear. However, recent research points to a finely tuned interplay between several cells in the hair follicle.

Hair progenitor cells are reported to release a protein called stem cell factor, which is a requirement for the production of pigment by melanocytes. In mouse studies, the researchers showed that if this protein is absent, hair color is lost.

Once the hair stops growing, the hair follicle undergoes dramatic structural changes and enters a rest period. During this process, melanocytes naturally die.

However, melanocyte stem cells in the hair follicle normally produce a new set of melanocytes at the start of the next hair growth cycle.

Once the new hair starts to grow, these melanocytes once again ensure that pigmentation is available. But when the melanocytes are damaged or absent, the hair that is produced lacks color and can look gray or white.

Hair growth after damage

Research has shown that human hair follicles that produce gray or white hair have higher levels of cellular damage caused by free radicals. In these follicles, melanocytes and melanocyte stem cells are absent.

In mice, when the DNA of melanocyte stem cells in the hair follicle were damaged, it resulted in permanent cell damage. These stem cells were then unable to reproduce.

Without the pool of stem cells, the next round of hair growth proceeds without melanocytes, resulting in gray hair.

Although it has not yet been possible to fully establish cause and effect during hair graying in humans, the accumulation of damage in melanocyte stem cells over time most likely leads to a loss of this cell population. Each hair follicle will eventually be unable to produce colored hair.

So, while it is inevitable that we will all lose our hair pigment one day, why do some of us go gray in our 20s, while some of us hold on to our colorful locks until our 50s? Research from 2016 showed that individuals with a certain variant of the gene interferon regulatory factor 4 are prone to earlier graying.

As with many of our other traits, we can thank our parents for passing their propensity for graying along to us.

Health benefits of sex

Type “sexual health” into a search engine, and it is likely that you will be bombarded with pages of articles covering anything and everything, from sexual norms and advice on relationships, birth control, and pregnancy, to information about STDs and how to avoid them. What is less often discussed, however, is the abundant physical and psychological health benefits of sex. We have put together a list of the top health benefits of sex, as backed up by science.

In exploring just how sex affects the mind and body, the list of potential benefits appears to be endless.

Aside from reproduction, pleasure, and intimacy, sex seems to have a positive impact on many life areas, including work, physical and cognitive performance, marriage, and happiness into our senior years. Sex may also have a positive effect on certain organs and conditions, as well as a preventive effect on some diseases.

For example, a recent study published in the Journal of Management found that maintaining a healthy sex life at home might boost job satisfaction and engagement at work.

Sex may also play a fundamental role in preserving a happy marriage, according to researchpublished in Psychological Science. Partners are suggested to experience a sexual “afterglow” that lasts for up to 48 hours following sexual intercourse. This afterglow is associated with higher levels of long-term relationship satisfaction.

Sex is also considered a significant form of exercise. Sex burns around 85 calories, or 3.6 calories per minute, according to a study published in PLOS One.

These few examples are a drop in the ocean of the numerous health benefits of sexual activity and masturbation that are presented in studies from around the globe. Medical News Today provide the low-down on the top evidence-based health benefits of sex.

1) Improves immunity

Participating in sex one to two times per week appears to be the optimum frequency to boost the immune system, according to research published in Psychological Reports.

Scientists can test how tough our immune systems are by measuring levels of an antibody called immunoglobulin A (IgA) in saliva and mucosal linings.

Study authors Carl Charnetski, from Wilkes University in Pennsylvania, and his colleague Frank Brennan found that people who had sex once or twice per week had a 30 percent increase in IgA. However, the same results were not seen in individuals who had sex more or less frequently.

Clifford Lowell, an immunologist at the University of California-San Francisco, says that people who are sexually active are exposed to more infectious agents than individuals who are not sexually active. The immune system responds to these infectious agents by producing more IgA, which may protect against colds and flu.

For those of you who have sex more or less frequently than the optimal amount, fear not. According to another study by Charnetski, petting a dog can also significantly raise IgA.

2) Good for the heart

Physical activities that exercise the heart are good for your health, and this includes sex. Being sexually aroused increases heart rate, with the number of beats per minute peaking during orgasm.
Men who have regular sex are 45 percent less likely to develop heart disease.

Men, in particular, have been shown to benefit from the effect of sex on the heart. A studypublished in the American Journal of Cardiology, involving men in their 50s, suggested that men who have sex at least twice per week have a 45 percent reduced risk of heart disease, compared with men who have sex less frequently.

The American Heart Association say that heart disease should not affect your sex life. Heart attacks or chest pain caused by heart disease rarely happen during sex and, for the most part, it is safe to have sex if your heart disease has stabilized.

The heart’s response to sex is comparable with mild to moderate effort encountered in daily activities, according to research published in the European Heart Journal. If you can take part in activities that have a similar impact on the heart – such as walking up two flights of stairs – without chest pain, then you can usually assume that it is safe to have sex.

More research is currently needed to draw connections between specific cardiovascular conditions and sex, particularly for women and older adults.

3) Lowers blood pressure

Research conducted by Michigan State University and published in the Journal of Health and Social Behavior found that sex in later years might reduce the risk of high blood pressure – at least for women.

Women in the study aged between 57 and 85 years who found sex pleasurable or satisfying were less likely to have hypertension. However, male study participants who had sex once per week or more were twice as likely to experience heart problems than men who were sexually inactive.

In another study published in Behavioral Medicine, researchers found that the act of hugging can help a person to maintain a healthy blood pressure.

According to the American Heart Association, high blood pressure increases the risk of heart attack and stroke and can also affect your sex life. High blood pressure has an impact on blood flow throughout the body and can prevent enough blood flowing to the pelvis.

In men, high blood pressure can lead to erectile dysfunction and in women, high blood pressure can lower libido and reduce interest in sex. It is considered safe to have sex if you have high blood pressure. However, if you are concerned or are having problems in the bedroom, seek advice from your doctor.

4) Relieves pain

A headache may often be used as a reason to avoid sex. However, before you reach for the painkillers, neurologists have found that sexual activity can relieve head pain associated with a migraine or cluster headache in some people.

[woman in bed with migraine]
Sex has been shown to ease the pain associated with migraines and cluster headaches.

The research was conducted by the University of Munster in Germany and published in Cephalalgia. In individuals with a migraine, 60 percent of people reported an improvement in pain after sexual activity, while 37 percent of people with a cluster headache reported an improvement.

The University of Munster researchers explain that sex triggering the release of endorphins is the mechanism behind the pain relief. Endorphins are the body’s natural painkillers and are released through the central nervous system, which can reduce or eliminate pain the experienced with a headache.

In other research published in Pain, women were found to experience reduced pain sensitivity and had an increased pain tolerance threshold when experiencing pleasure through vaginal self-stimulation.

5) Reduces the risk of prostate cancer

Men who frequently ejaculate could be protected against prostate cancer, the most common cancer among men in the United States.

Research led by Michael Leitzmann, from the National Cancer Institute in Bethesda, MD, and published in JAMA, discovered that men who ejaculated 21 times per month or more were a third less likely to develop prostate cancer than men who ejaculated between four and seven times per month.

Leitzmann and team have a number of theories as to why increased ejaculation may help to prevent prostate cancer.

The first theory is that frequent ejaculation may allow the prostate gland to clear out carcinogens, and materials that may orchestrate the development of carcinogens. Another theory suggests that regular drainage of prostate fluid stops crystalloid microcalcifications – which are associated with prostate cancer – from developing in the prostate duct.

Men who have more than 12 ejaculations per month may also benefit, although the researchers note that at this point, the research would not warrant recommending men to change their sexual behavior.

6) Improves sleep

Do you have trouble getting to sleep at night? Sexual activity could be just what the doctor ordered.

Insufficient sleep is a public health problem, according to the Centers for Disease Control and Prevention (CDC). Around 50 to 70 millionadults in the U.S. have a sleep disorder.

Sex could be the answer to help you achieve the recommended 7 to 9 hours of sleep per night.

During sex and orgasm, a cocktail of chemicals are released in the brain, which includes oxytocin, dopamine, and a rush of endorphins. Oxytocin, also known as the “cuddle hormone,” facilitates closeness and bonding, and it surges during sex and orgasm in both men and women.

After orgasm, it is thought that the effect of oxytocin, combined with the release of the hormone prolactin (which is linked to the feeling of satiety and relaxation), makes you feel sleepy.

In women, a rise in estrogen levels during sex has been shown to enhance their REM cycle, according to a study published in the Journal of Women’s Health.

In men, the prefrontal cortex – the area of the brain associated with alertness, consciousness, and mental activity – “switches off” after orgasm. According to a study published in Neuroscience & Biobehavioral Reviews, this process is connected with the release of oxytocin and serotonin, both of which have sleep-inducing effects.

Vitamin D guidelines can be changed

A new study finds that, contrary to popular belief, vitamin D-2 and D-3 do not have equal nutritional value. With vitamin D deficiency on the rise, the authors call for a rethink of official guidelines.

Vitamin D is a vital nutrient, helping the gut to absorb calcium while keeping calcium and phosphate at the right concentrations to support healthy bone growth and maintenance. Without adequate levels in the body, bones can become brittle and misshapen.

Low vitamin D levels have also been linked with a range of other conditions, including cardiovascular disease and cancer.

Vitamin D is not naturally present in many foods. Instead, the bulk of our requirement is synthesized in the skin after exposure to ultraviolet light from the sun.

Despite the importance of vitamin D, many people in the United States do not have sufficient levels in their bodies. For example, one study found that overall, more than 40 percent of the U.S. population were vitamin D deficient. So much so, that some authors have referred to vitamin D deficiency as a pandemic.

Furthermore, in one study published in 2009, only 3 percent of black people in their sample of thousands of U.S. individuals had the recommended vitamin D levels, representing a decrease of 9 percent over the previous 20 years.

For this reason, it is becoming increasingly important to understand how the vitamin works and to ensure that the right type of supplements are reaching individuals most at risk.

Not all vitamin D types are equal

There are two types of vitamin D, which are known as D-2 and D-3. The former is derived from plant sources, particularly fungi, while the latter comes from animal sources.

The two types of vitamin D are very similar, differing only in the structure of their side-chains, and it is generally accepted that both perform similarly well as a supplement. In fact, on the National Institutes of Health website, they write, “The two forms have traditionally been regarded as equivalent.”

Researchers from the University of Surrey in the United Kingdom recently set out to test whether or not this widely held belief is correct. They wanted to understand which of the two nutrients raises levels of vitamin D in the body most effectively.

The researchers measured vitamin D levels in 335 South Asian and white European women over two winter periods. They chose winter because, due to a reduction in sunlight exposure, vitamin D levels tend to be lower at this time.

The women were split into five groups: those consuming vitamin D-2 in a biscuit; those consuming vitamin D-3 in a biscuit; those consuming vitamin D-2 in a juice drink; those consuming vitamin D-3 in a juice drink; and those receiving a placebo.

The study found that vitamin D-3 was twice as effective at raising vitamin D levels in the body as vitamin D-2.

Participants who received the D-3 in a biscuit raised their levels of vitamin D by 74 percent, while those receiving the vitamin in juice saw a 75 percent increase. Those receiving D-2 had a 33 and 34 percent increase, respectively. The placebo group experienced a drop of 25 percent across the same period.

A boy or a girl? Baby’s sex may influence mother’s immunity

Does the baby’s sex influence the mother’s immune system? A new study investigates the link between fetal sex and the mother’s immune response to illness.
[woman has an ultrasound]
New research suggests that being pregnant with a girl may affect how the mother’s body responds to illness.

A team of researchers from Ohio State University Wexner Medical Center set out to examine whether or not there is a connection between the sex of the baby and the mother’s immunity.

The team was led by Amanda Mitchell, a postdoctoral researcher in the Institute for Behavioral Medicine Research at Wexner.

The research was triggered by both anecdotal evidence and scientific studies (referenced by the authors) that suggest that the sex of the fetus influences several physiological responses in the mother. Glycemic control, blood pressure, and cortisol levels have all been shown to differ according to the sex of the fetus.

In the new study, Mitchell and team examined 80 women in the early, middle, and late stages of their pregnancies. Of these future mothers, 46 were pregnant with males and 34 with females. Researchers exposed their immune cells to bacteria to see whether they responded differently depending on the sex of the fetus.

Female fetus raises pro-inflammatory cytokine levels

More specifically, Mitchell and her colleagues examined the levels of cytokines in pregnant women. Cytokines are signaling molecules that regulate immunity and inflammation.

They are sometimes called emergency molecules because they are released by the body to fight off sickness, as they help cells to communicate with each other when there is inflammation in the body. Cytokines are part of the body’s natural immune response, but they can cause disease when released persistently. This is similar to how inflammation is a crucial component of the immune response, but too much of it can cause achiness and fatigue.

The study analyzed cytokine levels both in the blood and in the bacteria-exposed laboratory sample.

The findings suggest that women pregnant with girls may experience more severe symptoms of certain illnesses.

“While women did not exhibit differences in blood cytokine levels based on fetal sex, we did find that the immune cells of women carrying female fetuses produced more pro-inflammatory cytokines when exposed to bacteria. This means that women carrying female fetuses exhibited a heightened inflammatory response when their immune system was challenged, compared to women carrying male fetuses.”

The increased inflammation noticed in this study could explain why women pregnant with female fetuses tend to have more severe symptoms of pre-existing medical conditions. Examples given by the researchers include asthma and allergies, which are both conditions appearing to be exacerbated when carrying a female fetus compared with a male one.