Sleep disorders may be linked to vitamin D deficiency and environmental toxins

Vitamin D is important for the hormone system and our sleep, but certain environmental toxins like phthalates, bisphenol A, and triclosan can disrupt our hormone balance and sleep quality. Lack of vitamin D can even exacerbate the harmful effect of the hormone disruptors and, according to a study published in Nutrients, this may have a negative impact on our sleep.

Phthalates, bisphenol A, and triclosan are widely used hormone disruptors that serve as plastic softeners and are found in things like plastic bags, plastic toys, rain clothes, and printed t-shirts. Bisphenol A is found in plastic drinking bottles, food can linings, and in plastic-based dental material. Triclosan, which is a polychlorinated compound, has anti-bacterial and anti-fungus properties and is found in toothpaste, soap, deodorants, textiles, and cleaning agents.
Everyone gets exposed to these and numerous other environmental toxins, which are also found in the water and accumulate in the entire food chain. It has been known for decades that these pollutants disrupt the hormone balance, including our sex hormones. Also, these compounds can affect our hypothalamus-pituitary-adrenal-axis that is important for healthy sleep. In addition, various environmental toxins have a so-called cocktail effect, which increases their harmful impact.
In recent years, science has been interested in looking into how phthalates and bisphenol A can disrupt our sleep by making it difficult to fall asleep and to enter the deep sleep stage, or make us wake up too frequently or too early, which means we don’t feel properly rested the following day.
An estimated 50 percent or more of the world’s population suffers from poor sleep. This can increase the risk of any acute and chronic problems such as tiredness, poor performance, infections, accidents, alcohol abuse, hypertension, diabetes, overweight, cardiovascular diseases, depression, anxiety, dementia, and other diseases. Although sleep disorders are so common, health authorities rarely look at them as a serious health problem.
Researchers are focused on vitamin D because this vitamin works like a steroid hormone and is also important for the interplay with the other steroid hormones, including cortisol, progesterone, and sex hormones. Vitamin D and the other steroid hormones are all made from cholesterol.
The type of vitamin D that we get from sun exposure or from supplements is converted in the liver into the form of vitamin D that is measured in the blood. Afterwards, it is converted again in the kidneys and other tissues into the active steroid form (1,25 (OH)2D3).
More and more research points to a link between vitamin D’s metabolism and several sleep-related health problems.
Earlier studies have shown that people who lack vitamin D generally sleep less and don’t sleep as well as people with sufficient vitamin D levels in their blood. However, science has not yet investigated the link between vitamin D, environmental toxins, hormone disruptors, and sleep disorders.

Hormone disruptors combined with vitamin D deficiency make sleep problem worse

In the new study, the researchers gathered data from 5,475 people aged 20-80 years, who were all part of the large American population study NHANES (National Health and Nutrition Examination Survey). By collecting lab data, the scientists got information about the participants’ serum vitamin D levels, and urine samples revealed the participants’ exposure to various hormone disruptors. The researchers adjusted for confounding factors such as smoking, alcohol, gender, BMI, education level, etc. They found that major exposure to various phthalates (mono-ethyl phthalate and mono-benzyl phthalate) and triclosan, either as separate compounds or in combination, was linked to an increased risk of reduced sleep and an increased risk of being vitamin D-deficient. Vitamin D-deficient participants who were exposed to triclosan also had reduced sleep duration compared with those who had plenty of vitamin D and were exposed to the same compound. The study results therefore suggest a link between exposure to environmental toxins and not getting enough sleep. Lack of vitamin D can make sleep disorders even worse.

Vitamin D-deficiency is widespread

• The diet only provides negligible amounts of vitamin D from sources like oily fish, cod roe, liver, eggs, and high-fat dairy products
• At northern latitudes during the winter period, the sun sits too low in the sky to enable vitamin D synthesis in the skin
• Many people need more vitamin D than the recommended intake level to optimize their blood levels of the nutrient (more than 75 nmol/L)
• It is advisable to limit your exposure to hormone disruptors

References:

Ruigi Zhou et al. Vitamin D Deficiency Exacerbates Poor Sleep Outcomes with Endocrine-Disrupting Chemicals Exposure: A Large American Population Study. Nutrition 2024