Cruciferous Vegetables for Thyroid Health
Written by: Dr. Pat Nardini, ND on December 6, 2013
"Eat your broccoli dear!" - Mom
Have you ever heard of the cruciferous family of vegetables? You might
not recognize the name, but I’m sure you’ll know the vegetables in the
I’ve received a lot of questions recently about cruciferous vegetables and how
they tie into the thyroid’s health. So, I decided to give my thoughts on this family
of veggies and how they fit into a healthy thyroid program.
The Cabbage Family
Cruciferous vegetables are related to cabbage and include:
• collard greens
• Brussels sprouts
• mustard (the seed, not the sauce!)
• cabbage(of course)
The great thing about these vegetables is the number of nutrients they contain,
including carotenoids (like beta-carotene, lutein, and zeoxanthin), vitamin C,
vitamin E, vitamin K, folic acid,minerals, and fibre.
But what’s even more impressive is their content of sulphur-containing
compounds called glucosinolates. After we eat them, these chemicals get
broken down into many other beneficial ones – indoles, nitriles, thiocyanates, and
isothiocyanates. The most-studied compounds include indole-3-carbonol
(anindole) and sulforaphane (an isothiocyanate). You may not have heard of
these before, but they provide some huge benefits!
The beneficial chemicals that we get when we eat cruciferous veggies have been
shown in lab studies to have anti-cancer activity. This is thought to happen
because these compounds protect DNA from damage, inhibit carcinogens, cause
apoptosis of cancer cells (programmed cell death), stop new blood vessel growth
(which feeds the cancer cells), and stop cancer from spreading.
Studies in humans have shown a benefit from consuming cruciferous vegetables
in the prevention of prostate, colorectal, lung, and breast cancers.
All over the internet, you can find references to how cruciferous vegetables are
“goitrogenic”. A goitrogen is a food or chemical that inhibits thyroid gland
function. This can lead to an enlargement of the thyroid called “goiter”.
Cruciferous veggies are classified as goitrogens based on speculation and on
one study, done on animals in 1983.
The animals that were fed large amounts of cruciferous vegetables had an
increased incidence of hypothyroidism (underactive thyroid). What is often not
mentioned is that this only occurred with animals that had a deficiency in iodine in
the first place!
Animals with normal iodine levels did not get hypothyroidism, even with high
cruciferous consumption. Further studies in humans have not been able to
demonstrate increased risk of goiter or thyroid cancer from high cruciferous
The Best of Both Worlds
If you have issues with your thyroid but would like to take advantage of the
awesome benefits of the cabbage family, there are two things to consider:
• Are you low in iodine?
• How can you prepare cruciferous veggies to minimize any potential
It’s possible to get tested for iodine to see if you’re low, but to maintain a healthy
level, consumption of kelp, seafood, and eggs can help. For more information on
the benefits of iodine, check out my last article. Making sure that you have
adequate iodine will help prevent thyroid problems from high cruciferous intake.
Cooking your cruciferous veggies will prevent the glucosinolatesin them from
getting broken down. This will prevent these compounds from negatively
affecting your thyroid, but it will also stop you from getting the anti-cancer
benefits. To get the most anti-cancer benefit out of these veggies, eat them raw
or lightly steamed. If you find that you eat them a lot (several times each day),
you may want to cook some of them more thoroughly as a precaution. Some of
these veggies, like kale, collard greens, and mustard greens, contain compounds
in them called oxalates, which can block mineral absorption. Cooking them
breaks down the oxalates and allows you to get your minerals.
The cabbage family offers us amazing health benefits. If we take a calm look at
them, they are a great addition to the diet, even for those with thyroid problems.
Until next time, this is Dr. Pat Nardini, putting “Your Health First!”
Dr. Pat Nardini, ND is a licensed Naturopathic Doctor in Toronto, Canada. His
practice focuses on promotion of the overall health of his patients through a wide
range of naturopathic methods. He has been in private practice now for over 10
years and specialises in thyroid conditions, primarily Wilson's Temperature
Syndrome. Read and see more naturopathy health articles and videos to learn more
about Dr. Nardini, his modalities, and how naturopathy can help you.