Leptin is a fat-burning hormone produced primarily in the liver. It helps regulate energy expenditure and body weight regulation. Leptin plays an important role in regulating appetite, satiety, and food intake.1–3 However, it may have other functions as well such as modulating immune function or even helping with wound healing.4 Leptin deficiency (obesity) is a growing problem worldwide.5,6
In humans, leptin levels are decreased in obesity due to increased adipose tissue mass and reduced physical activity.7 Leptin secretion from adipocytes decreases in obese individuals compared with lean individuals.8 Leptin resistance occurs when the amount of circulating leptin does not rise sufficiently to stimulate the hypothalamus to produce enough of its own hormone, called ob gene product (Ob), which regulates hunger and satiety signals.9 Ob gene products are secreted into the blood stream and bind to receptors on cells throughout the body.
When these receptors are activated, they cause changes in cell metabolism and cellular signaling that result in weight loss.10
The primary source of leptin is stored fat, but there is evidence that dietary factors also affect leptin production.11 In addition, there is some evidence that leptin can be produced locally within tissues such as muscle or brain tissue itself.12,13
Leptin and testosterone are considered to be metabolically antagonistic. This means that when leptin levels are high, testosterone levels are low.
When leptin levels are low, testosterone levels are high.14
There is an inverse relationship between testosterone and leptin; when leptin levels are high, testosterone levels are low, and when leptin levels are low, testosterone levels are high.15
Testosterone and leptin have a complex relationship as can be seen in the figure below. This relationship is important when considering the impact of nutrition on testosterone levels.16
Research has shown that supplementation with endurance exercise can increase leptin levels while resistance exercise can decrease it.17,18
Diet has a significant impact on leptin. A high-fat diet promotes weight gain and leptin resistance, which is also associated with obesity due to excess glucose intolerance.19 Undernutrition and starvation can also result in a decrease in leptin levels.20
While leptin is thought to play a role in male fertility, its exact function is still unclear.21 It has been shown that the introduction of leptin can reverse some of the detrimental effects that obesity has on male fertility.22 One thing that is clear, however, is the close relationship between testosterone and leptin.
Insulin and testosterone are also closely linked. When insulin levels are high, testosterone levels are low.
When insulin levels are low, testosterone levels are high.23,24
The pancreas secretes the hormone insulin to help the body control the amount of glucose (sugar) in the blood. Glucose is the main source of energy for the body’s cells.
Insulin causes cells to absorb glucose from the blood to be used as energy.25
A byproduct of this uptake is that it causes the cells to stop burning fat for energy and instead use up the glucose. The accumulation of fat that does not get used is stored.
In addition, insulin plays a role in other bodily processes that reduce testosterone levels.26
There are two major types of diabetes. Type 1 diabetes, which usually occurs in childhood, results from the body’s inability to produce insulin.
Type 2 diabetes, which usually occurs in adults, is the result of the body’s inability to respond appropriately to insulin.
Both types increase the risk of metabolic syndrome, with its associated low testosterone levels. The role of nutrition and lifestyle in the development of both types of diabetes is an active area of research.27
Thyroid hormones also play an important role in metabolism. Underactive thyroid (hypothyroidism) generally results in weight gain, low energy and depression.28
Thyroid hormones can be divided into T3 (triiodothyronine) and T4 (thyroxine). These hormones are made from an amino acid (tyrosine) and basically act to increase the metabolic rate, with effects on proteins, fats and carbohydrates.29
Research has shown that testosterone and thyroid hormones have a reciprocal relationship. When thyroid hormone levels are low, such as in hypothyroidism (low thyroid), testosterone levels are typically high.30
When thyroid hormone levels are high, such as in hyperthyroidism (high thyroid), testosterone levels are typically low.31
The relationship between testosterone and the thyroid gland is complex and not completely understood. There are a number of theories that attempt to explain the relationship, the most common of which is the hypothesis that androgens suppress thyroid activity.32
Other theories suggest that androgens actually increase thyroid activity.33 Clearly, there are other factors involved in the complex relationship between the endocrine systems.
Although the exact relationship is unclear, sufficient evidence exists to show that hypothyroidism can have an effect on androgen levels.
Hypothyroidism can cause a decrease in testosterone levels by decreasing the body’s ability to produce it.30,34
Conversely, hyperthyroidism can cause increases in testosterone levels by increasing the body’s ability to produce it.30,31
Quite simply, the interaction between testosterone and the thyroid gland is such that when one is low, the other is high, and vice versa.
The third major factor affecting testosterone levels is stress.35
Research has shown a strong relationship between stress and low testosterone.36-41 Stress causes a drop in testosterone levels.42
Stress is a common occurrence for most people. There are several different types of stress, including:
Acute stress: short-term, immediate and intense
short-term, immediate and intense Chronic stress: long-term and persistent
long-term and persistent Catastrophic stress: originates from a single event that causes extreme stress (i.e.
traumatic event, accident)
originates from a single event that causes extreme stress (i.e.
traumatic event, accident) Daily hassles: repetitive minor stressful events that occur daily
Stress can either be perceived as a positive or negative experience. It is the perception of the individual that dictates whether it is negative or positive.
People respond differently to stress; one person’s perceived negative stressor may be positive for another.
The response people have to stress depends on personality factors such as genetics, previous experiences and social learning (how they were taught to respond to situations).
Various regions of the brain are involved in the body’s response to stress. The most notable two are the hippocampus and the hypothalamus.
The hypothalamus triggers the release of corticotropin-releasing hormone (CRH) from the pituitary gland, which in turn secretes adrenocorticotropic hormone (ACTH) from the anterior pituitary. ACTH stimulates the release of cortisol from the adrenal cortex.
Stress has a negative effect on the production of testosterone by:
Stimulating the release of cortisol, which decreases testosterone Producing a negative perception of the stress, causing a lack of interest in sexual activity Acting on parts of the brain involved with sexual activity, such as the hypothalamus, to decrease desire
Stress usually causes a decrease in sexual desire. In males, it can lower testosterone levels.
This has a negative effect on libido because testosterone plays a large role in desire and sexual performance. The only effective way to manage this type of stress-induced low testosterone level is to eliminate the stressor or otherwise reduce its impact.
Stress does not affect everyone equally; some people are more stress-resistant than others. There are also differences in how the body responds hormonally and neurologically to stress.
Stress affects different parts of the brain in different ways. The prefrontal cortex is one area that is affected by stress; an overactive prefrontal cortex can actually reduce a person’s ability to handle stressful situations.
Other parts of the brain, such as the hippocampus, are affected in such a way that it impairs a person’s memory.
Several studies have indicated that high levels of stress over long periods of time can actually cause changes in the body. These changes are not always immediate and can sometimes take weeks or even months to become obvious.
These changes can cause long-term health problems such as cardiovascular disease, psychological disease and more.43
Stress can be classified into two types: good stress and bad stress. Good stress refers to short-term stressors that help a person’s body perform at its peak.
This type of stress usually involves tasks that involve physical exertion, competition or confrontation. The pituitary gland releases hormones in preparation for the body to handle this type of stress. This process is sometimes referred to as the fight-or-flight response.
The other type of stress is bad stress. This refers to long-term stress in daily life.
Some things that might cause this are financial issues, work overload and family problems. These things usually cause the body to release stress hormones that can have a negative effect on a person’s health if prolonged or if exposure to these types of situations is excessively common.
Stress affects different people in different ways. A person who is able to manage and deal with stressful situations will be less susceptible to its affects on the body.
Some people are more prone to anxiety than others, which means they might react to stress differently.
Stress can contribute to a number of medical issues, including:
Headaches Muscle pain Fatigue Ulcers Sleep disturbances Dizziness Weight gain Difficulty Concentrating Depression
The best way to handle stress is to eliminate the source. If this is not possible, it is important to find ways to manage the effects of stress.
Some ways to help with this are:
Learn relaxation techniques such as deep breathing, meditation, yoga or even exercising.
Practice gratitude. Research has shown that people who write down five things they are grateful for each day tend to be happier than those who do not.
Practice good self-care; this means feeding your body healthy food and getting enough rest and exercise.
Make time for fun and relaxation. This can help in relieving stress.
Spend quality time with friends or loved ones.
Give back to the community. Helping others can help take your mind off of things.
Take a break from time-to-time; even if it’s just for a few minutes. This can help to release tension and boost morale.
Work with your doctor on any medications or alternative treatments for stress, such as biofeedback, acupuncture or massage.
Stress can have both short-term and long-term effects on a person’s life. In some cases, it can be beneficial; however, most of the time stress is an enemy.
It’s important to engage in healthy ways to relieve stress and avoid sources of it whenever possible.
How a person reacts to situations is determined by his or her experiences and personality.
Personality is defined as a set of psychological and behavioral characteristics that remain relatively stable over time.
There are five main factors which influence personality development:
Genetics: refers to the biological heritage people inherit from their parents. Personality characteristics can be inherited, however, each child inherits a unique combination of these traits.
Environment: encompasses everything in a person’s life, such as hobbies, family and relationships. People are constantly exposed to different situations and experiences. Experience: is the most influential factor. It encompasses a person’s life experiences and the way they interact and react to people, places and things. Behavior: personality characteristics are revealed in the way a person acts. The way a person acts, dresses and speaks all reveal something about their personality.
As with stress, personality affects how a person responds to situations. People with optimistic personalities are more likely to remain calm than those with pessimistic personalities in stressful situations.
Personality also influences the types of illnesses a person develops. For instance, a person with a more aggressive or anxious personality is more likely to develop heart disease than someone with a calmer or more relaxed personality.
In some cases, a person’s personality may change drastically as a result of an illness or an injury to the brain. This is referred to as a “disorder.” Some common types of disorders include:
Anxiety Disorders: these disorders are characterized by feelings of extreme fear, worry or panic that interfere with daily life. A person suffering from an anxiety disorder typically experiences symptoms such as shortness of breath, rapid heartbeat, dizziness and nausea.
Depressive Disorders: these disorders are marked by a low mood, low self esteem and a loss of interest in daily activities. This disorder can sometimes lead to suicide.
Personality Disorders: people with this disorder have an inflexible personality that affects their ability to socialize.
Psychotic Disorders: this disorder is characterized by a disconnection from reality. A person with this disorder may suffer from hallucinations or delusions.
Mental disorders are characterized by a disruption in a person’s thoughts, feelings or behaviors. People with mental disorders may not be able to adjust to everyday life, or sometimes they adjust but their way of thinking is very different from others.
While many people have a pattern of thinking or behaving that is different from most other people and never suffer any negative effects as a result, people with mental disorders experience significant distress and disability that interferes with daily life.
Mental disorders are not a result of personal weakness and do not necessarily indicate a lack of willpower. All people experience sadness, grief, anxiety or other emotions from time to time, but people with mental disorders experience these feelings to a degree where they begin to interfere with daily life.
While a mental disorder may be caused by a chemical imbalance, life experience or genetics, the underlying cause of the disorder does not excuse the negative behavior. A person suffering from a mental disorder is just as responsible for their actions as someone without a disorder is.
There are a variety of treatment options available for mental disorders including therapy and medication.
It is important to remember that while a mental disorder may make a person more likely to commit a crime, the vast majority of people with mental disorders are not violent and only a small percentage of all crimes are committed by persons suffering from mental disorders.
Mental disorders affect a large percentage of the population and there is still much to learn about them. It may be years before doctors can pinpoint specific causes of each disorder and develop targeted treatments, but recognition of the signs and getting help is the first step towards helping those who suffer from mental illness.
We rely on the public to be aware of the signs and symptoms of mental illness and to report any suspicious activity as early intervention is the key to preventing more tragic events from occurring.
Thank you for your attention.
If you or someone you know is displaying signs of mental illness or suicidal tendencies, please take the time to call 1-800-273-8255 to speak to a counselor.
May god bless the victims and their families.
NOTE: The following pages were found in the same room as the above presentation. It contains handwritten notes, presumably from the killer.
My mother hated me. She always told me I “wasn’t right.” She was right of course.
I wasn’t right. I was different. It started when I was little. I didn’t like to play with other kids. I didn’t like the games they wanted to play. I had trouble relating to them. I was alone a lot.
I started withdrawing into fantasy. I had an overactive imagination.
I’d always make up games and adventures that I would enjoy. I started getting really into reading. That’s how I got my name. My teacher misheard it when I told her and she thought I said I loved to read “lesbian” books. I didn’t know what that meant but I was too embarrassed to tell her she was wrong so I just said it was my name.
I didn’t really know what lesbians were at the time either, but I found out. And I also found out that’s what I was.
I played alone a lot and had no friends. The other kids were mean to me. They would make fun of me and I would always just sit there and take it. I was too scared to fight back or tell them to stop. I didn’t understand it, but I still get scared easily.
I started getting really interested in girls at around the age of 10. I didn’t know why, but I soon found out.
The internet has a way of telling you what you need to know. I learned what being a lesbian was and that’s what I was. Unfortunately, most people don’t agree with that. Thanks to them I was bullied all throughout school.
I had to move schools five times because the bullying was so bad. I wanted to kill myself so many times but I couldn’t bring myself to do it.
I hated myself, but other than my sexual orientation, I didn’t really know why.
They say if you want to hide something hard to find, you hide it in plain sight. That’s what they did.
They hid the clues right in front of me and I didn’t even realize it until it was too late.
I grew up watching my mom suffer through domestic abuse. She would always blame herself and refused to leave my dad.
It wasn’t until I got a little older that I finally learned what he was really like. He had multiple affairs and was physically and mentally abusive towards her. She never deserved any of it.
I grew up in a house of lies. I couldn’t trust anyone.
Everyone seemed fake to me. I had trouble making friends in high school and later at college. I was so alone and no one seemed to understand me, except for one person.
Samantha was my only real friend. We met during our freshman year of college.
We had some of the same classes and we ended up sitting next to each other. We hit it off really well. We both loved music and would spend time talking to each other about it.
She was the only person I really felt comfortable with. I trusted her.
I should’ve known better.
I found out later that she was behind everything. She was the one who poisoned me, made me see all those doctors, told everyone those awful things about me.
After all the hell she put me through, I still wanted to try to help her.
She killed herself two weeks ago. I knew she was suicidal, but I didn’t know she was serious.
She left a note saying it was all my fault. She couldn’t even face me with everything.
I feel so…
so lousy. I don’t know what to do with myself anymore. I’ve tried to keep going with my life, but it’s getting harder. I’m so tired of running and hiding.
I’m sorry I lied. I’m done now.
“I’m sorry, Delilah.”
You close your eyes.
And then you’re gone.
Sources & references used in this article:
Don’t Count Calories to Lose Weight: The Body Fat Set Point Theory by K Cann – breakingmuscle.com
Leptin & Ghrelin–The 2 Key Hunger Hormones by BT Basics, YGTAS Back – rudymawer.com
Beyond Bigger Leaner Stronger: The Advanced Guide to Shattering Plateaus, Hitting PRs, and Getting Shredded by M Matthews – 2014 – books.google.com
the no-bs guide to workout supplements by FSA Best
The 3 Key Reasons Women Need to Pin-Point Their Regime (Training & Nutrition) by M Matthews – 2013 – books.google.com