Hormone found to switch off hunger could help tackle obesity

mymedicplus — Thu, 26 Nov 2020 06:30:36 +0000

Source – https://www.hindustantimes.com/

A hormone that can suppress food intake and increase the feeling of fullness in mice has shown similar results in humans and non-human primates, says a new study.

The study was published in the journal eLife.

The hormone, called Lipocalin-2 (LCN2), could be used as a potential treatment in people with obesity whose natural signals for feeling full no longer work.

LCN2 is mainly produced by bone cells and is found naturally in mice and humans. Studies in mice have shown that giving LCN2 to the animals long term reduces their food intake and prevents weight gain, without leading to a slow-down in their metabolism.

“LCN2 acts as a signal for satiety after a meal, leading mice to limit their food intake, and it does this by acting on the hypothalamus within the brain,” explains lead author Peristera-Ioanna Petropoulou, who was a Postdoctoral Research Scientist at Columbia University Irving Medical Center, New York, US, at the time the study was carried out and is now at the Helmholtz Diabetes Center, Helmholtz Zentrum Munchen, Munich, Germany. “We wanted to see whether LCN2 has similar effects in humans and whether a dose of it would be able to cross the blood-brain barrier.”

The team first analysed data from four different studies of people in the US and Europe who were either normal weight, overweight or living with obesity. The people in each study were given a meal after an overnight fast, and the amount of LCN2 in their blood before and after the meal was studied. The researchers found that in those who were of normal weight, there was an increase in LCN2 levels after the meal, which coincided with how satisfied they felt after eating.

By contrast, in people who were overweight or had obesity, LCN2 levels decreased after a meal. Based on this post-meal response, the researchers grouped people as non-responders or responders. Non-responders, who showed no increase in LCN2 after a meal, tended to have a larger waist circumference and higher markers of metabolic disease — including BMI, body fat, increased blood pressure and increased blood glucose. Remarkably, however, people who had lost weight after gastric bypass surgery were found to have a restored sensitivity to LCN2 — changing their status from non-responders before their surgery, to responders afterwards.

Taken together, these results mirror those seen in mice and suggest that this loss of post-meal LCN2 regulation is a new mechanism contributing to obesity and could be a potential target for weight-loss treatments.

After verifying that LCN2 can cross into the brain, the team explored whether treatment with the hormone might reduce food intake and prevent weight gain. To do this, they treated monkeys with LCN2 for a week. They saw a 28% decrease in food intake compared with that before treatment within a week, and the monkeys also ate 21% less than their counterparts who were treated only with saline. Moreover, after only one week of treatment, measurements of body weight, body fat and blood fat levels showed a declining trend in treated animals.

“We have shown that LCN2 crosses to the brain, makes its way to the hypothalamus and suppresses food intake in non-human primates,” concludes senior author Stavroula Kousteni, Professor of Physiology and Cellular Biophysics at Columbia University Irving Medical Center. “Our results show that the hormone can curb appetite with negligible toxicity and lay the groundwork for the next level of LCN2 testing for clinical use.”

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Is It Safe to Take Melatonin Every Night?

mymedicplus — Sat, 07 Nov 2020 06:42:02 +0000

Source – https://www.healthline.com/

How it works
Dosages
Risks of nightly doses
Side effects
Multiple doses
Interactions
When to seek care
Bottom line

Melatonin is a hormone that your body naturally produces. It plays a role in regulating your sleep-wake cycle.

There’s also a lab-made version of melatonin that’s available as an over-the-counter supplement. Some people use melatonin supplements to help with sleep problems like jet lag and insomnia.

In this article we’ll explore how exactly melatonin works and whether it’s safe to take melatonin supplements every night.

How does melatonin work?

Natural melatonin is predominantly made in your pineal gland, which is located in your brain. Light exposure inhibits the production of melatonin, but darkness stimulates it.

Melatonin levels in your brain begin to increase at dusk as the sun goes down and darkness falls. They reach their peak levels in the middle of the night and start decreasing as dawn gets closer.

The action of melatonin inhibits signals in your brain that promote wakefulness. This helps encourage sleep by making you feel tired or drowsy as you get closer to bedtime.

Because of melatonin’s sleep-promoting effects, melatonin supplements are used to treat a variety of sleep problems. These can include:

insomnia
jet lag
shift work sleep disorder
delayed sleep-wake phase disorder
sleep problems in children with autism or attention deficit hyperactivity disorder (ADHD)

What’s a safe dosage?

The Food and Drug Administration (FDA) doesn’t regulate melatonin as a drug. Because of this, there’s limited information on the optimal, safe dosage of melatonin.

In fact, the doses of melatonin supplements that have been used in various scientific studies vary widely, from 0.1 to 10 milligrams (mg)Trusted Source. One 2017 review defines a typical dose of melatonin to be between 1 and 5 mgTrusted Source.

Melatonin typically takes 1 to 2 hours to work, so it’s often taken up to 2 hours before bedtime.

If you’re looking to try melatonin for the first time, it may be best to begin with a lower dose. Your doctor can help recommend a safe dose for you to start with.

Melatonin for children

Like melatonin for adults, there’s not much information on the optimal, safe dosage for children. Dosage may also vary depending on a child’s age. One 2016 reviewTrusted Source suggests the following age-based dosages 30 to 60 minutes before bedtime:

1 mg for infants
2.5 to 3 mg for older children
5 mg for adolescents

Because there aren’t clear dosing guidelines regarding melatonin for children, be sure to speak to your child’s pediatrician before giving melatonin to your child.

Melatonin for older adults

The amount of melatonin your body produces decreases with age. Because of this, melatonin supplements may be helpful for older adults who are having trouble falling asleep.

Researchers are still looking into the optimal melatonin dosage for older adults. One 2016 review of sleep aids for older adults suggests a dosage of 1 to 2 mg of immediate-release melatonin 1 hour before bedtime.

What to know about dietary supplements and safety

The FDA classifies melatonin as a dietary supplement, meaning that it’s regulated less strictly than a regular drug. For dietary supplements, label claims and product safety don’t have to meet FDA approval before they’re marketed.

A 2017 studyTrusted Source of 31 different melatonin supplements found that the actual melatonin content of 71 percent of the products didn’t match the claim on the label. Additionally, 26 percent of products contained serotonin, which can be potentially harmful even in small doses.

When shopping for melatonin supplements, look for products that are “USP verified.” United States Pharmacopeia (USP) is an independent organization that works to ensure proper quality and dosing of dietary supplements.

Are there any risks involved with taking melatonin every night?

According to the National Center for Complementary and Integrative Health (NCCIH), short-term use of melatonin supplements appears to be safe for most adults and children. However, information on the effects of long-term melatonin supplements is limited.

Some studiesTrusted Source have indicated that long-term melatonin use in adults may cause mild side effects when compared to a placebo. Studies into the effects of long-term melatonin use in children remains limited.

Because melatonin levels naturally decrease at the beginning of puberty, there’s some concern that long-term melatonin use in children may delay puberty onset. However, more researchTrusted Source is needed.

What happens if you take too much melatonin?

Melatonin is generally safe. However, mild side effectsTrusted Source can sometimes occur, particularly if you take higher doses or extended-release formulations.

The side effects of melatonin can include:

feeling drowsy or sleepy
headache
dizziness
nausea
increased urination or bedwetting (children)

Some less common side effects of melatonin include:

irritability
abdominal cramps
mild tremors
feelings of depression or anxiety
confusion or disorientation
low blood pressure (hypotension)

If you experience side effects from melatonin, stop taking it and speak with your doctor. They may recommend using a lower dose or trying out an alternative medication or sleep aid.

Is it safe to take more than one dose during the night?

You may be wondering what happens if you take a dose of melatonin and find that you still can’t fall asleep. Can you take another dose?

While taking an additional dose is unlikely to cause harm, it may increase your risk for experiencing unwanted side effects.

If you find that melatonin isn’t helping you fall asleep, stop using it. Your doctor may be able to suggest different medications or strategies to help you fall asleep.

Can melatonin interact with other substances?

There are some important things to know about melatonin, its interactions with other substances, and when it’s best to avoid it. Let’s take a closer look.

What medications and substances does melatonin interact with?

Melatonin may interact with several different types of medications, including:

Blood-thinning medications. Taking melatonin with blood-thinning medication may increase your risk for bleeding.
Epilepsy medications (anticonvulsants). Melatonin may make these medications less effective.
Immunosuppressants. Melatonin can potentially interfere with immunosuppressive drugs.
Diabetes medications. Melatonin use can affect blood sugar levels.
Blood pressure medications. Blood pressure may get worse when melatonin is taken with these medications.
Contraceptive drugs. Birth control pills may increase the risk of side effects from melatonin.

Because melatonin supplements can make you tired and drowsy, avoid mixing them with:

other sleep aids
central nervous system depressants
alcohol

Are there any people who should avoid taking melatonin?

There’s limited research into the safety of using melatonin supplements during pregnancy. Also, while melatonin is a normal component of breast milk, there’s little research into the effects of taking melatonin supplements while breastfeeding.

Because of this, it’s best to avoid taking melatonin if you’re:

pregnant
planning to become pregnant
breastfeeding

Additionally, it’s important to speak to your doctor before using melatonin if you have:

an autoimmune condition
epilepsy
kidney disease
liver disease
had a previous allergic reaction to melatonin

When to see your doctor about sleep issues

It’s a good idea to schedule an appointment with your doctor or healthcare provider if you notice that you:

frequently have trouble falling asleep or staying asleep at night
often feel drowsy or tired during the day
have trouble performing your daily activities

Your doctor will work with you to discuss your sleep routine and lifestyle habits. They may also ask you to keep a sleep diary to track the amount of sleep you’re getting over a period of time.

It’s also possible that your doctor will perform a physical exam and order blood tests. These can help them rule out a medical condition that may be causing your sleep issues.

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