Vitamins taken by pregnant women contain toxic ingredients linked to autism and cancer, a new study has found.
Researchers tested 47 different prenatal vitamins – 32 over-the-counter products and 15 prescription products – purchased from popular online and brick-and-mortar stores.
They measured the amounts of choline and iodine in each product in the laboratory and compared this to what was on the label.
Shockingly, they found that some products contained levels of heavy metals that were higher than expected.
Thirteen had too much cadmium, seven products had too much arsenic and two had too much lead. Many others listed incorrect dosages or did not contain ingredients they claimed.
A study this year found that higher levels of cadmium in the urine during early pregnancy were consistently associated with an increased risk of autism in their children at age three.
High levels of cadmium have also been linked to kidney damage, bone fragility, lung disease and several forms of cancer.
Commenting on the findings, published in The American Journal of Clinical Nutrition, lead researcher Laura Borgelt said: ‘During pregnancy, many women rely on prenatal vitamins and minerals to support their health and their baby’s development.’
Vitamins targeted at pregnant women could do more harm than good, with toxic ingredients leading to a range of health complications from autism to cancer
But she added that the “presence of pollutants”, especially heavy metals, was “concerning”.
“Our findings highlight a significant gap between what is on the labels and what is actually in the products, underscoring the urgent need for stronger regulatory oversight in this area,” said Dr. Borgelt.
Many of the heavy metals found in the prenatal vitamins exceeded the limits set by the US Pharmacopeia, a nonprofit organization that provides recommended levels for a variety of topics.
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The organization recommends arsenic (2.5 mcg per oral daily dose), lead (0.5 mcg per oral daily dose) and cadmium (0.5 mcg per oral daily dose).
Seven products contained levels of arsenic above that limit, two contained lead levels that were unsafe and 13 contained too much cadmium.
The FDA lists a cadmium tolerance level of 0.21 to 0.36 micrograms of cadmium per day per approximately 2 pounds of body weight — or about 25 micrograms for a 154-pound person.
When it comes to lead, high exposure to the metal can cause significant damage to the brain, kidneys and reproductive system.
Exposure to high levels of lead during pregnancy can cause babies to be born prematurely, have low birth weight, and possibly have developmental delays due to damage to the developing brain and nervous system.
No safe level of lead exposure exists, but the FDA’s acceptable daily intake of lead in food is approximately 8.8 micrograms for adults.
Excess amounts of arsenic were also found in seven of the prenatal vitamins.
Exposure to even low levels of arsenic can cause long-term problems such as high blood pressure, thickening and discoloration of the skin, problems with blood vessels, numbness or pain in the nerves and heart disease, as well as cancer.
There are no federal limits for arsenic in most foods, although the FDA has issued industry guidelines on limits for certain foods that are more likely to contain arsenic.
The authors say that while there is a need for more oversight to ensure supplements contain the right ingredients, prenatal supplements are still important to take during pregnancy.
When the researchers checked to see if the prenatal vitamin labels were correct, they found that there were some errors in the nutrient amounts listed.
Choline amounts were listed on 12 of 32 (37.5%) nonprescription product labels and zero of 15 prescription product labels.
Only five of the products labeled as containing choline had the correct dosage on the label. Two of them had much more than stated.
That’s concerning because excessive amounts of choline can cause low blood pressure and liver damage, which can be even more serious during pregnancy.
Dr. Borgelt said: ‘Among the most crucial nutrients for fetal development are choline and iodine.
“However, some prenatal vitamins may not contain the exact amounts listed on the label and some may not contain choline or iodine.”
She added: ‘Our research aims to help women better understand the nutritional benefits of prenatal supplements, allowing them to make more informed choices and select the best options for their health and the well-being of their baby.’
‘We are one of the first studies to measure the actual amounts of choline and iodine in a large sample of prenatal supplements.
When checking for iodine — which in large amounts can cause thyroid inflammation and thyroid cancer — they found that most prenatal vitamins contained less than advertised.
And few delivered the correct amount: 53 percent of products listed the iodine content, but only four (16 percent) products contained the claimed amount of iodine on the label.
The authors say that while there is a need for more oversight to ensure supplements contain the right ingredients, prenatal supplements are still important to take during pregnancy.
They recommend double-checking the ingredients or working with a doctor or healthcare provider to choose the prenatal supplement.
The study did not mention the brands of supplements.