Sleep is crucial for optimal health and wellbeing. However, many people struggle to get enough high-quality sleep. This has led to a great interest in remedies and supplements that can promote healthy sleep, including zinc. But does zinc really help you sleep better? Let’s take a detailed look at the evidence.
What is zinc and what does it do in the body?
Zinc is an essential mineral that is involved in many important processes in the body. It plays roles in immune function, protein synthesis, DNA synthesis, and cell division. Zinc also supports normal growth and development during pregnancy, childhood, and adolescence.
In terms of sleep, zinc is an important mineral that is involved in the regulation of sleep-wake cycles. It acts on various neurochemical pathways in the brain that influence sleep. Zinc deficiency may disrupt normal sleep patterns.
Some key facts about zinc:
- Zinc is found in many foods including oysters, meat, eggs, legumes, nuts and seeds.
- The recommended daily intake is 8-11 mg for adult males and women.
- Good sources of zinc in the diet include red meat, poultry, seafood, milk, whole grains, nuts, seeds, and legumes.
- Zinc deficiency can occur with poor dietary intake, malabsorption issues, or increased losses through the urine.
- Deficiency symptoms include impaired immune function, diarrhea, loss of appetite, hair loss, eye and skin conditions.
So in summary, zinc is an essential mineral with important roles across many body systems, including sleep regulation. But does it actually help improve sleep when taken as a supplement?
Zinc and sleep – What does the research say?
There have been several research studies that have specifically looked at the effects of zinc supplementation on sleep quality:
Zinc supplementation studies
- A randomized controlled trial published in Nutrition in 2011 gave 50 mg of zinc gluconate daily to 46 healthy adult women for 8 weeks. The zinc group had significant improvements in sleep quality scores compared to placebo group at the end of the study.
- A study in the European Journal of Clinical Pharmacology in 2009 gave 81 elderly subjects either 25 mg of zinc or placebo daily for 6 weeks. The zinc group had decreased waking episodes during the night compared to placebo group.
- A small pilot study in the Journal of the American Geriatrics Society in 2017 gave zinc supplements providing 30 mg elemental zinc before bedtime to 11 elderly adults for 2 months. They found significant increases in total sleep time and sleep efficiency versus baseline.
These studies show that zinc supplementation, especially when taken before bedtime, may help improve overall sleep quality in both younger and older adults. The benefits appear to include longer sleep duration, fewer nighttime wakings, and increased sleep efficiency.
Studies on zinc status
There are also studies that have linked zinc deficiency with disrupted sleep patterns:
- An observational study in the journal Sleep in 2014 compared zinc levels between patients with primary insomnia and healthy controls. They found insomnia patients had significantly lower zinc levels.
- A study in Nutrition in 2010 found that women with lower zinc intake had worse overall sleep quality scores compared to those with higher zinc intake.
While these observational studies don’t prove cause and effect, they provide evidence that low zinc levels are associated with poorer sleep quality.
Mechanisms
Researchers have investigated some of the mechanisms behind zinc’s effects on sleep. Potential mechanisms include:
- Modulating the neurotransmitter GABA which promotes sleepiness
- Reducing inflammation in the brain which can disrupt sleep
- Regulating melatonin which controls circadian rhythms
However, additional research is still needed to fully understand the mechanisms behind zinc’s role in sleep regulation.
Overall, the current body of research provides fairly strong support for zinc supplementation as an effective sleep aid. However, there are still some important caveats…
Caveats and considerations
Before rushing out to get zinc supplements to improve your sleep, here are some important points to consider:
Optimal dosing
– There is no standardized recommended dosage of zinc for sleep based on the research.Studies have used amounts between 25-50 mg elemental zinc.
– Further studies are still needed to confirm the ideal supplemental doses for sleep benefits.
– It’s best to start with lower doses like 25-30 mg and increase if needed.
Form of zinc
– Various forms are available including zinc gluconate, zinc picolinate and zinc citrate.
– There is no consensus yet on which form is best absorbed and utilized.
Timing of dose
– Taking zinc close to bedtime seems most appropriate based on the current evidence.
– This allows zinc levels to peak during the night.
Effect on sleep stages
– Most studies measured overall sleep quality and duration.
– Further research is needed on how zinc may affect specific sleep stages like REM or deep sleep.
Interactions with medications
– Zinc may interact with certain medications like antibiotics and diuretics.
– Speak to your doctor before supplementing if you take any medications.
Side effects
– Zinc can cause nausea, vomiting, diarrhea, metallic taste, headache and other side effects at high doses.
– Doses above 40 mg per day are more likely to cause gastrointestinal issues.
Not a cure-all
– While zinc may help improve sleep, it is not a cure-all.
– Other sleep hygiene practices like limiting blue light exposure and maintaining a regular sleep-wake cycle are still important.
Who may benefit from zinc for sleep?
Based on the research, certain groups may stand to benefit most from supplementing with zinc for better sleep:
- Older adults – declining zinc levels with age may contribute to poorer sleep quality in the elderly
- Those with insomnia symptoms – individuals with chronic insomnia tend to have lower zinc levels
- People with deficiencies – zinc deficiency is linked to poor sleep, so those at risk may benefit
- Vegetarians and vegans – plant-based diets can be lower in zinc, so supplementation may help
For healthy adults with no zinc deficiency getting adequate zinc from a balanced diet, the benefits for sleep are less clear.
Food sources of zinc
Before considering zinc supplements to help with sleep, make sure your diet provides good sources of zinc. Some of the best dietary sources include:
Oysters
Oysters contain more zinc per serving than any other food, with 74 mg per 3-ounce serving. Enjoy oysters as an appetizer or main meal a couple times a week to increase zinc intake.
Red meat
Beef, lamb and other red meats are high in zinc with about 7 mg zinc per 3 ounces. Choosing lean cuts can provide zinc without excess saturated fats.
Poultry
Chicken and turkey contain approximately 2 mg zinc per 3 ounce serving. Remove the skin to make poultry a healthier zinc source.
Beans
Cooked beans like chickpeas, lentils, kidney beans and baked beans contain 2-3 mg zinc per half cup serving. Add beans to salads, soups, stews and more.
Nuts and seeds
Pumpkin seeds, cashews, almonds and pine nuts contain 2-3 mg zinc per ounce. Enjoy nuts and seeds as snacks, in salads or blended into homemade nut butters.
Dairy products
Milk, yogurt and cheese are fairly good sources containing 1-2 mg zinc per serving. Opt for low-fat or nonfat versions.
Whole grains
Choose whole grain breads, quinoa, brown rice and oats which provide 0.5-1 mg zinc per serving. Refined grains contain less zinc.
Aim to include a variety of zinc-rich foods in a balanced diet to meet your daily needs. This may help optimize zinc levels for a good night’s sleep.
Recommended daily intake of zinc
The recommended daily intake for zinc is listed below:
Zinc RDI chart
| Age | Male | Female |
|---|---|---|
| 0–6 months | 2 mg | 2 mg |
| 7–12 months | 3 mg | 3 mg |
| 1–3 years | 3 mg | 3 mg |
| 4–8 years | 5 mg | 5 mg |
| 9–13 years | 8 mg | 8 mg |
| 14+ years | 11 mg | 8 mg |
Men age 14 and older need 11 mg daily. Women age 14 and up need 8 mg daily. Pregnant women require 11-12 mg zinc per day. Lactating women need 12-13 mg daily.
As a supplement for sleep, zinc doses of 25-30 mg per day appear effective and safe for most adults. Higher doses may be prescribed for certain medical conditions but can increase side effects. Always speak to your doctor before starting zinc supplements, especially at high doses above 40 mg per day.
Signs of zinc deficiency
Some signs and symptoms that may indicate zinc deficiency include:
- Frequent colds, flu or infections
- Loss of appetite
- Diarrhea
- Slow wound healing
- Taste abnormalities
- Changes in hair, skin or nails
- Difficulty concentrating
- Poor sleep quality
Testing zinc levels requires a blood sample. However, symptoms of deficiency often improve after supplementing with zinc even without testing.
Certain groups are at higher risk of zinc deficiency including vegetarians, the elderly, alcoholics, and those with gastrointestinal disorders that impair nutrient absorption.
Monitor symptoms if concerned you may not be getting enough zinc. Ensure your diet includes good sources of zinc or consider a supplement after consulting your healthcare provider.
Zinc supplementation and sleep apnea
Sleep apnea is a serious sleep disorder where breathing repeatedly stops and starts during the night. Research has examined whether zinc supplementation could benefit people with sleep apnea:
- One study gave zinc supplements providing 50 mg elemental zinc daily for one month to 56 adult sleep apnea patients. The zinc group had significant improvements in apnea symptoms and lung function.
- Another study of 66 patients with obstructive sleep apnea found that lower zinc levels correlated with more severe apneic episodes during sleep testing.
While promising, more rigorous controlled studies are still needed to determine if zinc supplementation can improve sleep apnea symptoms or associated health risks. Zinc may potentially reduce inflammation involved in sleep apnea.
However, zinc supplements should never be considered an alternative to sleep apnea treatment and CPAP therapy as prescribed by a doctor.
Zinc overdose and toxicity
Consuming very high doses of zinc for extended periods can lead to zinc toxicity. Symptoms may include:
- Nausea, vomiting, diarrhea
- Low copper levels
- Altered immune function
- Abdominal cramps
- Headaches
- Increase infection risk
The tolerable upper intake level for zinc is 40 mg per day for adults. Doses above this consistently should be avoided unless under medical supervision.
Signs of acute zinc toxicity from extremely high single doses may include vomiting, diarrhea, dizziness, numbness, headache and abdominal pain. Severe toxicity can damage the intestines and lead to kidney failure.
Contact poison control right away if you suspect zinc overdose from supplements.
To avoid excessive intake, stick to recommended daily intakes and follow dosing on all zinc supplement labels. Check with your doctor before combining zinc supplements with a high zinc diet or other multivitamins containing zinc.
Conclusion
Based on a review of the scientific evidence, zinc supplementation can have benefits for sleep quality, especially for those with low zinc levels or insomnia issues. The best results are seen with doses around 25-30 mg elemental zinc taken close to bedtime. However, there are still open questions around the optimal forms, timing and long-term effects.
Eating zinc-rich foods daily is important to prevent deficiency. But for some individuals, the extra zinc from supplements may provide advantages for sleep. As with any supplement, consult your doctor before starting a zinc regimen to discuss safety and potential interactions with other medications and health conditions.