Boron

Boron (which is also known as boron in the supplement sector) has the chemical abbreviation B, has the atomic number 5 in the periodic table of elements and is chemically considered a non-metal, albeit with some metallic properties. After carbon, it is the hardest of all elements. Boron is used in the production of pesticides, lubricants and insulating materials such as glass wool. It also plays a role in the reinforcement of plastics and light metals, e.g. in aircraft construction and aerospace.

Boron was discovered in 1808 by the two French chemists Joseph-Louis Gay-Lussac and Louis Jacques Thénard and the Englishman Sir Humphrey Davy. It is the 37th most abundant element in the earth's crust. It is mainly found as boric acid and its salts, such as borax (sodium tetraborate); it does not occur in elemental form. It occurs as borosilicate in the gemstone tourmaline. The melting point of pure boron is 2180° C. It is essential for plants and animals. The fact that boron is also important for human nutrition was only discovered in the 1980s.

Functions in the body

Boron has a number of vital functions in plants and animals. Whether this also applies to humans has not yet been conclusively proven. Many nutrition experts do not consider boron to be an essential nutrient (even though boron is essential for growth and has a positive effect on health) because boron does not have a "defined biochemical function". However, recent research has found that boron is important for immune function, bone health, brain health and hormone production. However, there is no officially recommended daily intake (1, 2, 3).

Boron compounds appear to be suppliers of hydroxyl groups (chemically -OH) and in this role may support the production of a number of hormones, most notably the sex hormones estrogen and testosterone. Boron compounds also appear to inhibit protein degradation, i.e. to stabilize proteins in the cell plasma. This function can also explain the positive effect of taking boron in the clinical picture of osteoporosis, because it can probably slow down the breakdown of proteins in the bones, of which the cytoskeleton consists, among other things. Boron probably also plays a role in the immune system, possibly because it promotes the stability or formation of antibodies.

Food sources of boron

Boron is found in milk, dairy products, drinking water, fruit, nuts and vegetables. Dietary boron intake varies depending on where you live. In Europe, daily boron intake can be as low as 0.8 mg per day, while in the USA it can be as high as 7 mg per day (3). Many foods contain sufficient amounts of boron to make a difference to your health. Raisins, hazelnuts and dried apricots have some of the highest density of boron per weight.

Foods rich in boron include (3, 4):

• Soy 2.8 mg / 100g
• Prunes 2.7 mg / 100g
• Raisins 2.4 - 2.8 mg/ 100g
• Peanuts, hazelnuts, almonds, 1.6 - 2.4 mg/ 100g each
• Dates 1 mg/ 100g
• Red wine (0.1 liter) 0.85 mg/ 100g
• Oysters 100 - 400 mg/ 100g

Many other types of fruit and vegetables contain smaller amounts of boron. If you consume sufficient amounts of these foods, you may not need boron supplements. (4).

Metabolic functions and potential health benefits of boron

Scientists are investigating the role of boron as an ultra-trace element and how it may contribute to human health. Scientific research suggests that boron may be important for the following functions. However, this does not mean that you necessarily need to supplement boron. Instead, you should work with your doctor or nutritionist to determine if your diet is deficient in boron and if dietary changes are recommended.

Boron is important for bone health

Boron prevents the breakdown of vitamin D and thus increases the amount of vitamin D available in the body. As vitamin D is essential for bone health, boron is also important for maintaining strong bones (3). One study found that the bones of people who took boron supplements were much stronger than the bones of people who did not take boron supplements. Boron supplements also increased the mineral density of the bones of female athletes (5, 6). In postmenopausal women, boron supplements reduced calcium loss and reduced the rate of osteoporosis (3, 7, 8).

Boron could support wound healing

Boron appears to be important for wound healing. It may be involved in the production of fibrous proteins such as collagen and other compounds that help repair damage to skin, bone and other tissue types (3). A gel containing boron is currently being investigated for use in the treatment of diabetic foot ulcers. The gel has been shown to kill microbes such as yeast and other fungi and accelerate the process of wound repair and tissue growth in laboratory settings (9). Boron also induces the growth of bacteria-killing white blood cells called phagocytes. These cells help fight infections and kill pathogens (10). Faster and better wound healing has been observed in animals fed a diet rich in boron (2).

Boron could have an effect on the body's sex hormones

Testosterone and oestrogen are considered to be the two most important sex hormones. They are often referred to as male and female sex hormones, although both have many functions in both men and women (11, 12). Boron could influence the amount and effect of both testosterone and estrogen in the human body. It may also have an effect, albeit weaker, on a third hormone called FSH.

Testosterone

Testosterone, the "male sex hormone" has a seemingly endless list of functions. It determines the sex of the child in the womb. It leads to the onset of puberty in boys. It is a steroid that builds muscle. It coordinates the sex drive. It improves memory and cognition - and more (11). Low testosterone levels are much more serious in men than in women, which may be due in large part to the fact that men have higher testosterone levels to begin with. Low testosterone levels can cause weakness, fatigue, depression, sexual dysfunction, reduced muscle mass, anemia, bone disease, facial and body hair loss, and insomnia (11).

After one week of daily boron supplementation, 8 healthy men showed significantly higher testosterone levels in their blood. According to the authors of the study, boron may deactivate a protein called sex hormone binding globulin (SHGB), the levels of which were significantly reduced in these men after only six hours following their first boron intake (3, 13). Boron supplements also significantly increased testosterone levels in postmenopausal women. This effect was most dramatic when the women's diet was low in magnesium. Testosterone is sometimes used to treat sexual dysfunction in postmenopausal women, but only if these women also have sufficiently high estrogen levels (3, 14, 15).

Oestrogen

Oestrogen, the "female sex hormone", is vital for both men and women, although oestrogen levels are much higher in women. Estrogen initiates puberty in girls and determines the sexual behavior of women. In men, oestrogen is important for sexual development and healthy sperm (16, 17, 18). Estrogen also maintains brain function, controls appetite and supports thyroid, bone and skin health (19, 20, 21, 22). Abnormally high or low estrogen levels can cause health problems. High estrogen levels can increase the risk of cancer and stroke, while low estrogen levels - especially in women - can cause memory problems, irregular menstrual cycles, bone disease and depression (23, 24, 25, 26, 27, 28, 29).

After menopause, estrogen levels drop dramatically. As a result, women are susceptible to many of the risks mentioned above during this phase of their lives (30). Boron may or may not interact with and increase estrogen levels. One study of postmenopausal women showed a significant increase in blood estrogen levels after boron supplementation, while another study showed reduced estrogen levels after boron supplementation (14, 31). Rather than having direct effects on estrogen and its levels, boron may increase the body's sensitivity to estrogen. It may bind to a type of estrogen receptor called estrogen receptor beta, or ER-β, and increase its activity. ER-βb is important for the health of the uterus, immune system, digestive tract, lungs and prostate and may help the body fight cancer. (3, 32, 33, 34, 35, 36).

Follicle stimulating hormone (FSH)

Follicle stimulating hormone, or FSH for short, is important for sexual development and function as it triggers the growth of eggs and sperm (37, 38). Both low and high FSH levels can cause health problems. Diseases and conditions associated with low FSH levels include polycystic ovary syndrome, hypopituitarism and hyperprolactinemia (39, 40, 41). Limited evidence suggests that boron may increase FSH levels. However, this has only been studied in rats exposed to toxic levels of boron. The rats also lost the function of their sexual organs and developed reduced fertility (42).

Boron is important for brain health

Boron deficiency decreases brain activity in both animals and humans. In one study, people with extremely low boron levels showed a shorter attention span and poorer short-term memory. They performed worse in tests of dexterity and coordination (3). These changes in brain activity are similar to those caused by malnutrition and heavy metal poisoning (3). Boron is undoubtedly important for brain health, which is why some scientists recommend boron supplementation in case of deficiency (2).

Boron could help with arthritis

Estimated arthritis rates correlate negatively with the amount of boron consumed in the diet. In areas of the world where daily boron intake is 1 mg or less, arthritis rates range from 20 to 70%. In areas of the world where daily intake is between 3 and 10 mg, arthritis rates range from 0 to 10% (5). People suffering from arthritis also have lower concentrations of boron in their joints than people without arthritis (5). In a study of 20 arthritis patients, half of the subjects reported an improvement in symptoms after boron supplementation of 6 mg per day. Of the members of the placebo group, only 10% reported an improvement (5).

Boron could help with kidney stones

Kidney stones are crystallized solids that form in the kidneys. If they become too large, they can cause severe pain, vomiting and blood in the urine. In combination with antioxidants, hydration and nutrition, boron may help flush out kidney stones (43, 44, 45). In a small human study, 10 mg of boron per day increased the rate of kidney stone excretion. Those who took boron also experienced less pain when the kidney stones were excreted (46).

Daily requirement

There is currently no binding information on the recommended daily requirement of boron, but it is estimated to be 1 - 7 mg per day for adults.

Supplement dosage

Commercially available boron supplements are usually in the form of capsules or drops that provide 2 to 6 grams of boron per serving, with 3 mg being the most common dosage. To be on the safe side, adults should never take more than 20 mg of boron orally per day (3).

Requirements in sport

Boron supplementation is said to increase the body's testosterone levels by up to 300%. Unfortunately, that would be too good to be true! An increase in testosterone and oestrogen levels has only been proven in menopausal women. Supplementation of up to 5mg a day has been shown to be absolutely sufficient. If this is included in a multivitamin/mineral preparation, you can take it, otherwise a boron preparation alone is irrelevant as a dietary supplement.

Consequences of a boron deficiency

Deficiencies in any important nutrient will cause health problems and these problems can help us to better understand the normal function of a nutrient. Since there is no official recommended daily intake for boron, it is difficult to identify symptoms of boron deficiency or to attribute a boron deficiency. According to some scientists, a boron deficiency could cause problems with bone development, growth and healing. When people don't have enough boron, their bone cells can't lay down new bone tissue properly, which could lead to bone diseases such as osteoporosis and rickets (3). Many of the symptoms of boron deficiency are similar to those of vitamin D deficiency. This overlap suggests that boron may interact with the skeletal system via vitamin D metabolism (3).

Safety and side effects

Supplemented boron at recommended levels is probably safe even for sensitive groups of people such as children and pregnant women. Supplements usually contain boron derived from natural sources. Some of these forms include calcium fructoborate, calcium borogluconate, boron citrate or boron complexes. Boron is often combined with salts such as calcium to provide synergistic benefits for bone health. Boron toxicity is rare in humans because boron is easily excreted from the body (47, 48).

Precautions and warnings

Boron is likely safe for adults and children when used at doses below the upper tolerable limit. There are concerns that doses above 20 mg per day may impair fertility in men. Boric acid, a widely used form of boron, is probably safe when used vaginally for up to 6 months. However, boric acid can cause a burning sensation in the vagina. Since boric acid is toxic if swallowed, boric acid must never be taken orally! The upper tolerable limit, the maximum dosage at which no harmful effects are to be expected, is 20 mg per day for adults and pregnant or breastfeeding women. For adolescents between the ages of 14 and 18, this amount is 17 mg per day. For children between 9 and 13 years the upper tolerable limit is 11 mg per day, for children between 4 and 8 years 6 mg per day and for children between 1 and 3 years 3 mg per day. An upper tolerable limit has been set for infants.

Pregnancy and lactation: Boron is safe and harmless for pregnant and lactating women between 19 and 50 years of age when used at doses below 20 mg. Pregnant and breastfeeding women between the ages of 14 and 18 should not take more than 17 mg of boron per day. Higher amounts could be harmful and should not be used by pregnant and breastfeeding women as they have been linked to birth defects. Intravaginal boric acid has been associated with a 2.7 to 2.8-fold increase in the risk of birth defects when used during the first 4 months of pregnancy.

Hormone-sensitive diseases such as breast cancer, uterine cancer, ovarian cancer and endometriosis: Boron could act like estrogen. Therefore, if you suffer from a disease that could be aggravated by estrogen, you should avoid boron in the form of supplements or foods high in boron.

Kidney disease or problems with kidney function: You should not use boron supplements if you suffer from kidney problems. The kidneys have to work hard to excrete boron.

Overdose/poisoning

An overdose of boron can lead to symptoms of poisoning, whereby a distinction is made between acute and chronic poisoning. The symptoms of acute boron poisoning are cramps, vomiting (emesis), meningitis, diarrhea and collapse. Chronic boron poisoning leads to gastritis, liver and kidney damage, pulmonary hemorrhage, pulmonary edema, water retention throughout the body, drowsiness, confusion and depression.

It also causes an itchy dermatitis (skin inflammation) called psoriasis borica. A reliably effective antidote is not known. Gastric lavage or the administration of medicinal charcoal for oral ingestion is not reliably effective. The treatment of poisoning is therefore primarily symptomatic. For example, in the case of severe vomiting, the loss of fluids and electrolytes must be compensated.

Interactions

Oestrogen

Boron could increase oestrogen levels in the body. Taking boron in combination with oestrogen could cause excessively high oestrogen levels.

Iodine

There is some evidence that boron may interact with the thyroid gland. Boron could compete with iodine for uptake into the thyroid gland and reduce thyroid function. If thyroid function is impaired, it becomes larger in order to compensate for the hypothyroidism. Over time, a goitre can form. In rare cases and in large quantities, boron could contribute to hypothyroidism and the formation of a goitre (49).

Vitamin D

Boron prevents the breakdown of vitamin D. In this way, it increases the amount of time each vitamin D molecule remains in the blood and, as a consequence, the total amount of vitamin D available to the body (3). Most people need to worry more about vitamin D deficiency than vitamin D toxicity, but too much of a good thing can still be dangerous. Supplementing with too much vitamin D can cause nausea, vomiting, diarrhea, constipation, bone pain, irregular heartbeat and other symptoms. For this reason, taking too much vitamin D and boron should be avoided (75, 76).

Conclusion

Boron is an ultratrace element: it is relatively rare and makes up only a tiny fraction of the human diet, but it is essential for bone and brain health, as well as reproductive health. Like vitamin D deficiency, boron deficiency can cause problems with bone growth and healing. Boron in the diet may also play a role in hormone regulation. Boric acid - a different form of boron than the forms found in supplements - is used as a suppository to treat yeast infections, although this is not recommended as there are many safer and more effective remedies. Boric acid is toxic in large quantities and should never be taken orally.

Borax - which is also not found in supplements - is toxic to the kidneys, brain and reproductive system, but it is still used in some areas of the world as a food additive with the code E285. For most people there is probably no need to supplement boron as it is found in many foods such as fruit, nuts, beans and peas. Some people already consume 7 mg of boron through their diet alone and doctors recommend consuming no more than 20 mg of boron per day. Boron poisoning is rare because boron is easily excreted in the stool and urine. Some research suggests that boron may interact with the thyroid gland. If you supplement with boron, make sure you also get enough iodine to prevent thyroid problems. Boron also enhances the effects of vitamin D. Too much vitamin D and boron taken together can cause health problems.

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