A diet expert specializing in cancer treatment and prevention has warned that supplement addicts could be putting themselves at risk of contracting the disease.
Nichole Andrews, 38, a Washington-based registered dietitian and nutritionist specializing in oncology, shared a video on social media explaining why vitamins can be toxic.
He told his 316,000 Instagram followers that high doses of some vitamins can transform into harmful molecules called free radicals, which can trigger a cascade of cell damage that leads to cancer.
Those who have survived cancer are particularly vulnerable because of their high genetic risk of secondary tumors, he added.
‘Unfortunately, cancer survivors fall prey to many people who sell supplements.
“They try to get you to take all these different supplements to say it’s the way to detoxify and reduce cancer.”
“You can get a very high dose of a micronutrient with just one pill, whereas with food you never reach that toxic level.” she added.
‘Do not take supplements unless you have a real deficiency that your doctor will show you and prove by lab results.
“Supplements do not decrease the risk of cancer, they can increase it to that high level.”
Several studies echo their concerns and advise against excessive consumption of vitamins.
One 2023 study published in The Journal of Clinical Investigation, suggested that antioxidants such as vitamin C and E may actually help tumors grow.
These two nutrients play a vital role: vitamin C is important for wound healing and the health of skin, blood vessels, bones and cartilage; and vitamin E for eye health and immunity.
Vitamin C is found in foods like broccoli and citrus fruits and vitamin E is found in nuts and seeds.
While these vitamins are not a concern when consumed at the levels found in food, consuming more than your body needs by taking supplements could help cancer flourish.
One study suggested that antioxidants like vitamin C and E may actually help tumors grow.
Researchers at Karolinska Institutet, a medical university in Sweden, injected mice with lung cancer cells before feeding them increasing doses of vitamins C and E through drinking water.
They then performed regular ultrasounds to monitor the formation of blood vessels that help cancer cells form a solid tumor.
The results showed that the vitamins boosted a protein in the body that helped increase blood supply to tumors, helping them grow.
Another 2015 review A study by experts at the University of Colorado found that those who took extra vitamins and minerals were more likely to have health problems.
One vitamin in particular, beta-carotene, a supplement advertised as an immune system booster, was found to increase the risk of developing lung cancer and heart disease by up to 20 percent.
But that was only when people took more than the recommended dose of 7 mg a day.
The substance gives yellow and orange color to fruits and vegetables and is converted to vitamin A in the body.
However, in high doses, the vitamin can be dangerous and increase the risk of lung cancer in people who smoke or have been heavily exposed to asbestos at work, according to the NHS.
Nicotinamide riboside (NR), a form of vitamin B3, is advertised to have anti-aging effects, as well as being able to reduce high cholesterol and blood pressure.
But a study in mice at the University of Missouri-Columbia found that NR increased the risk of breast cancer and caused the disease to spread to the brain, which is fatal.
The body converts the supplement into nicotinamide adenine dinucleotide (NAD+), an enzyme that is key to providing energy to cells. But cancer cells can also feed on this energy.
To test this theory, the researchers gave genetically modified mice with cancer 400 times the standard recommended daily dose of 250 mg of NR.
The researchers monitored their cancer cells, T cells (a type of ‘fighting’ white blood cell) and healthy tissue.
NR increased the spread of cancer cells to the brain in nine of 11 mice, compared to only three of 12 mice in the control group that did not receive the supplement.
When they applied the technique to breast cancer cells, they found that the risk of developing cancer also increased.
In 2019, one of the UK’s top pharmacists and former government adviser unleashed a scathing attack on supplements, declaring them “untested and unproven”.
Dr Paul Clayton, clinical pharmacologist, told MailOnline: ‘Of all the vitamins, multivitamins, omega 3s, vitamin C tablets and the like, there is no evidence to support any of them.
‘The only thing they all have in common is that they don’t work and have no evidence to support them. When you test any of these things, they do nothing.
‘These products are sold by companies that don’t really know what they are selling, and they are bought by customers who don’t really know what they are buying.
“But in the case of nutritional supplements this does not matter, because they do not contribute anything anyway, they only benefit the consumer’s pocket.”