Tag Archives: metabolism

How Light Effects Your Metabolism by Jim Rollince


A guest contributor, Jim Rollince, shares this informative article on how the amount of light in our environment can have a big impact on health.

Jim writes:

Ambient Light During Sleep and The Affect on Metabolism

By Jim Rollince of Gym Source, distributor of home gym equipment, including treadmills, ellipticals and other home gyms.

Frustrated that your exercise routine and constantly calorie counting has not yielded any weight loss results? Are you in fact gaining more weight then before you began exercising and monitoring your food consumption? The key to your weight gain could be a result of an external factor that you never took into account, the exposure to light at night.

New research in sleep science has shown that prolonged exposure to light during the regular nighttime sleeping hours may cause weight gain. This weight gain occurs independent of daytime calorie consumption and physical activity.

These research findings came out of a study by the Proceedings of the National Academy of Sciences. The study tested animals, and the findings have begun to raise discussion from the scientific community based on whether the human body experiences metabolic sluggishness and weight gain as a result of too much light exposure at night.

A research team from Ohio State University discovered that mice exposed to a dim light during the course of a night for roughly a two-month period, gained 50 percent more body mass than mice exposed to a regular light-dark cycle. “Although there were no differences in activity levels or daily consumption of food, the mice that lived with light at night were getting fatter than the others,” said Laura Fonken, a neuroscience doctoral student at Ohio State and director of the study.

Although the lab mice were exposed to nighttime light they did not become less active nor eat more. However, they did eat at times when they normally wouldn’t. In fact, in one part of the study when the mice were exposed to light at night and then restricted from eating with the exception of their normal feeding times, they did not experience more weight gain.

“Something about light at night was making the mice in our study want to eat at the wrong times to properly metabolize their food,” Randy Nelson, professor of neuroscience and psychology at Ohio State and co-author of the study.

The researchers found that levels of the stress hormone corticosterone were not different among the mice exposed to the dim light and mice exposed to standard light-dark. This finding was surprising for the research team since corticosterone is connected to changes in metabolism. The research has shown that changes in metabolism have the potential to cause weight gain independent of corticosterone levels.

What is the link between dim light at night and fat-causing changes in one’s metabolism? The Ohio State research team postulates that the presence of light during the night works to disrupt hormone melatonin. Hormone melatonin plays a significant role in the functioning of the metabolism. To this end, light exposure at night could in fact disrupt expression of clock genes, which aid in controlling the time animals choose to be active and eat.

Dr. Nelson furthers her comments by saying that if her team’s research results are confirmed, eating late at night is a serious contributing factor to obesity. “Light at night is an environmental factor that may be contributing to the obesity epidemic in ways that people don’t expect,” he said. “Societal obesity is correlated with a number of factors including the extent of light exposure at night.”

Past research similar to this study have been prolonged television and computer use as contributing risk factors for obesity. Yet these studies were centered in the idea that engaging in prolonged television or computer usage contributed to a lack of physical activity. The current connection between weight gain and the light coming from a TV or computer, is related to the disruption of the metabolism via the negative bodily effects of getting too much light exposure at night and eating at the wrong time.

“Clearly, maintaining body weight requires keeping caloric intake low and physical activity high, but this environmental factor may explain why some people who maintain good energy balance still gain weight,” Dr. Nelson’s press statement.

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Adopted Children Experience Early Sexual Maturity


Puberty occurs when areas within the brain awaken beginning a cascade of hormone signals which conclude with the gonads (ovaries and testicles) increasing their production of the female and male sex hormones estrogen and testosterone. Under the influence of these hormones a child begins the transition from childhood to sexual maturity. In boys puberty is associated with a growth spurt, the appearance of facial, axillary (arm pit) and pubic hair, acne, deepening of the voice, growth of the testicles and penis while girls undergo a growth spurt, develop breasts, acne, pubic and axillary hair, and growth of the clitoris.

Historical data shows the average age of puberty today is many years sooner than in previous generations. Most experts attribute earlier puberty to better nutrition. A recent article in metabolism.com reviewed how “over-nutrition” accelerates obese children into puberty sooner (referred to as precocious puberty) than normal weight children. The latest studies on causes of precocious puberty suggests that a child’s social environment also exerts an important influence on the timing of puberty. Researchers in Madrid publishing in The Journal of Clinical Endocrinology and Metabolism 95:4305 2010 analyzed the age of puberty in normal children, adopted children and children whose families immigrated (children not adopted but subject to high levels of personal stress) to Spain. Adopted children were 25 times more likely than other groups of children to undergo precocious puberty (breast development before the age of 8 years in girls, and boys under 9 years of age with testicular growth). Over-all girls were 11 times more likely than boys to demonstrate precocious puberty.

Researchers speculate that socio-emotional stresses early in life of children who are later adopted result in changes in the brain that cause premature maturation of vital nerve pathways. This early brain maturation later results in stimulation of the pituitary gland, turning on the hormone pathways that cause puberty. This seems strange to me because various forms of deprivation in childhood can also delay puberty. For example, girls who have anorexia remain child-like in their body development and may fail to menstruate even into their late teens. A decade ago I studied hormone levels in adults during the stress of illness and surgery and found this lowered the sex hormone levels in their blood. This makes sense from an evolutionary point of view because during stressful conditions nature wisely cuts off the reproductive hormones. Why make babies if the environment is hostile in some way? Why the opposite occurs in children under stress of adoption is an interesting but unanswered question.

Gary Pepper, M.D.,
Editor-in-Chief, metabolism.com

Dr. Oz’s “Metabolic Makeover” Dishes Empty Calories


I want to help Dr. Oz not criticize him. Criticizing Dr. Oz is like criticizing Mother Theresa. He is uniformly worshiped by the media and his huge audience. He comes across as someone truly wanting to be helpful. So if I come across as being critical of him think of it as constructive criticism.

Yesterday, as I waited in the checkout line at Walmart, I saw a popular woman’s tabloid with a full page photo of Dr. Oz. The headline with the picture was “Dr. Oz’s Metabolic Makeover”. This intrigued me because I can use new information of this kind in my daily office encounters, so I bought the magazine. Imagine my surprise when, reading through the 2 page article, I didn’t find a single word from the great and powerful Oz. Instead a nameless author offered a summary of “Dr. Oz’s body-transforming secrets!”. What were Dr. Oz’s secrets? Take Vitamin D, fish oil, calcium, multivitamins, get enough sleep, and eat food with anti-oxidants low in carbs and sugar. In conclusion a dietitian put together a few simple recipes for meals based on a 1400 calorie per day diet. That’s it folks. That’s all she wrote!! Nothing even remotely new or body transforming. There was not a single original or inspirational thought to be found. Not even a single quote from the medical guru. I doubt whether he even read the article himself.

Dr. Oz was trained as a cardiac surgeon. It takes years of dedication and hard work to achieve that goal. In his mind must have been a desire to save people’s lives by literally taking them to the brink of death and bringing them back healthier than they were before. What this article says to me is that Dr. Oz has allowed himself to become the Kim Kardashian of medicine. A pretty but empty headed celebrity offering nothing of real value. His full page photo in this magazine is the portrait of an almost cynical drive to grab a few dollars from the pockets of adoring fans. What kind of deal do you have, Dr. Oz? Do you get a few pennies for each magazine sold? Do you really need the money, the fame, the glory that this kind of exploitation provides?

Nobody got hurt by this, you might say. That is true if you have time and money to waste. I know that many people would rather get up to date information they could use to get healthy and donate the money they wasted on this article to better causes.

We expect something more from you Dr. Oz. Shake off your advisers and entourage. Stand up for the person you originally sought to be.

Gary Pepper, M.D.
Editor-in-Chief, Metabolism.com

Changes in Hormones After Gastric By-Pass Speed Weight Loss and Lower Blood Sugar


It seems obvious that cutting away part of the stomach and intestine should cause weight loss. With a smaller stomach and less intestine fewer calories can be absorbed per day causing weight loss. Surgeons who perform gastric by-pass were puzzled however, by how fast their patients showed metabolic improvement after undergoing this procedure. They noticed many of their diabetic patients could be taken off diabetic medication immediately after surgery before weight had been lost. Scientists looking into this phenomena discovered unsuspected ways gastric by-pass improved metabolism.

The intestines produce hormones which regulate blood sugar and appetite. GLP-1 is among the best known of these intestinal hormones. GLP-1 is the basis of a whole new generation of medications used to treat diabetes such as Byetta, Victoza, Januvia and Onglyza. GLP-1 lowers blood sugar, stimulates the pancreas and reduces appetite. After gastric by-pass increased amounts of GLP-1 are produced by the remaining intestine. In a study published in the Journal of Clinical Endocrinology and Metabolism (95:4072-4076, 2010), researchers at St. Luke’s Hospital in New York discovered that levels of oxyntomodulin, another intestinal hormone that suppresses appetite and acts like GLP-1 on blood sugar levels, is doubled after gastric by-pass.

These exciting discoveries help explain why obese diabetics can often be sent home without any medication to control blood sugar immediately after undergoing gastric by-pass surgery. Although most insurance plans do not cover gastric by-pass surgery, dramatic improvements in patients after the procedure with greatly reduced medication costs may convince insurance companies that paying for the procedure will result in better outcomes and save them money in the long run.

Gary Pepper, M.D.
Editor-in-Chief, metabolism.com

Growth Hormone Deficiency Tied to Obesity and Accelerated Aging in Young Adults


Due to the potential for abuse and high cost, growth hormone treatment in adults is the subject of much controversy. I believe that treating adults with growth hormone deficiency is many times an appropriate and beneficial choice. Firming up my conviction for treating adult growth hormone deficiency is a recent study conducted in the Netherlands and UK published in the Journal of Endocrinology and Metabolism (JCEM 95:3664-3674, 2010). The researchers compared Body Mass Index (BMI), waist circumference, triglycerides, and HDL (good cholesterol), between normal adults and those with low growth hormone levels due to deficient pituitary function (hypopituitarism). All measurements of obesity and lipid metabolism were significantly worse in the young adults (younger than 57 years) with growth hormone deficiency compared to normal adults of a similar age.

As I pointed out in previous articles at metabolism.com, growth hormone levels naturally decline as we get older. The authors of the present study note that growth hormone levels decline 14% per decade in adults. I conceive of this as one of the ways nature gets rid of us after we complete our biological/reproductive functions, since without growth hormone our muscles, immune and nervous systems, decline, leading to death. It’s planned obsolescence… what is typically referred to as aging. In the recent study senior citizens have equivalent levels of obesity and abnormal lipid metabolism as young adults with growth hormone deficiency. The authors note the effect on the body of growth hormone deficiency in young adults is equivalent to 40 years of aging. The theory that growth hormone functions to preserve our tissues during youth and aging results from its absence, appears confirmed by these results.

Most normal young adults aren’t growth hormone deficient and the population that would qualify for growth hormone treatment from this group is small. What about older adults with low growth hormone who are troubled by the “natural” decline in their body function? Should or could we treat this much larger population with growth hormone? It is my experience that private and federal insurers will not pay for this treatment regarded as “cosmetic”. On the other hand, there will be physicians who will comply with a request for growth hormone treatment from individuals who possess enough cash and motivation. Less affluent or determined individuals will have to contend with natural aging just as our ancestors have done for thousands of years.

This information is for educational purposes only and is not intended as medical advice or treatment.

Gary Pepper, M.D.
Editor-in-Chief, metabolism.com.

Chubby Neck Becomes the New Normal


After reading the latest research on the metabolic hazards associated with chubby necks I am more sensitive to the size of people’s necks then ever. Of course I look at the size of my patient’s neck but people who I pass in the street or supermarket may find me staring. Watching TV a few days ago I was startled by a series of people in one commercial for Quicken Loans who definitely qualify for the metabolic high risk category based on neck chubbiness. One after another the characters in this commercial walk on, outdoing each other in this physical trait. Has the chubby neck become the new normal? If so, the incidence of diabetes and heart disease is sure to continue to rise.

Let me know if you agree with my impression, or am I biased by being an endocrinologist?

Gary Pepper, M.D.
Editor-in-chief, Metabolism.com