thyroid

RECENT POSTS

Thyroid Doc: Kale Risks ‘Theoretical’ But In Reality, Very Low To Minuscule

bittermelon/flickr

bittermelon/flickr

This post — “The Dark Side of Kale (And How To Eat Around It)” — went wildly viral this week, generating huge traffic and high passions over this once minor but now hotter-than-hot vegetable. Among the accusations from readers were charges that the post was “dubious and dangerous” and that I was, in effect “discouraging Americans from eating vegetables” (my children would disagree).

Still, for a medical reality check, I turned to a doctor who specializes in treating the thyroid.

(Before we get to him, for background, my post was inspired by an earlier piece in The New York Times on potential thyroid problems linked to kale and other cruciferous vegetables, called “Kale? Juicing. Trouble Ahead.” This article was troubling to me since I, too, am a devoted kale fan.)

OK, back to the thyroid expert, who points out that this debate is particularly timely since January is Thyroid Awareness Month.

Dr. Jeffrey Garber is chief of endocrinology at Harvard Vanguard Medical Associates, and lead author of the latest clinical practice guideline on hypothyroidism in adults. He agreed to answer a few more questions on the kale-thyroid connection.

I’d sum up Dr. Garber’s take on the whole kale issue pretty simply: It’s probably unwise to embrace a long-term, pound-a-day raw kale habit, but even if you do, you will, in all likelihood, be fine. (Especially if you live in the U.S., where iodine deficiency isn’t a huge problem, and if you don’t have a family history or predisposition to thyroid disorders.)

“If one isn’t a food faddist or predisposed to a thyroid problem (family history, prior diagnosis) the risks are very low,” Garber said. And, he adds, if you have any concerns at all, check in with your doctor for a simple thyroid test.

Here, lightly edited, is our Q&A:

RZ: In plain terms, what’s the connection between kale, a cruciferous vegetable, and thyroid function?

JG: There are many substances that can interfere with the way the thyroid functions. Goitrogens, as in those that promote goiter, make up one of these categories.
(There’s an enormous amount of interest in environmental goitrogens, like BPA and other substances, but that’s another story: We’re talking about dietary goitrogens here.)

When you get into the way goitrogens can affect the thyroid directly there are three general ways (and all relate to iodine, which is what thyroid hormone is made from):

1. the way the thyroid picks up the iodine;

2. the way the thyroid produces the hormone once the iodine is in the thyroid;

3. the way thyroid hormone is secreted into the bloodstream.

When you look at dietary goitrogens, they interfere with one or more of these three steps.

OK, so kale is one of these so-called “goitrogenic” foods, right?

Yes. Continue reading

The Dark Side Of Kale (And How To Eat Around It)

(photofarmer/Flickr)

(photofarmer/Flickr)

The headline in The New York Times made my heart sink: “Kale? Juicing? Trouble Ahead.

Confession: I’m one of those Vitamix-loving, green-smoothie worshipping, kale bandwagoners. I brim with holier-than-thou pride when my kids eat raw kale (no dressing, even!) and thick kale-laden shakes while other children snack on sugary GoGURT squeezes and suck on juice boxes.

I am not alone. Presidents and stars are kale-lovers too.

Kale, in case you haven’t noticed, is health-conscious America’s “it” vegetable. Raw, blended, sauteed or in chip or “crunch” form, it appears to be the manna of celebrities: Gwyneth and Jennifer devour it while Kevin Bacon recently declared [it’s] “the age of kale.” In an astutely reported feature called “Stars Who Love Kale,” US Weekly quotes Bette Midler saying: “Kale is burning up the veggisphere.”

Even the Obamas dined on kale salad at their Thanksgiving feast, notes The Washington Post.

But apparently there’s trouble in cruciferous paradise.

Writing for The Times, Jennifer Berman reports on the dark side of kale, and how the health-infused, veggie Eden she’d carefully built over years began to crumble:

Imagine my shock, then, at my last physical, when my doctor told me I had hypothyroidism, common in women over 40. When I got home I looked up the condition on the Internet and found a list of foods to avoid. Kale, which I juiced every morning, tops the list, followed by broccoli, cauliflower, cabbage, Brussels sprouts and collard greens — the cruciferous vegetables I consumed in large quantities because they are thought to prevent cancer, which runs in my family. And flax — as in the seeds — high in omega 3’s, that I sprinkled on cereal and blended in strawberry almond milk smoothies. Also forbidden: almonds and strawberries, not to mention soy, peaches, peanuts, corn, radishes, rutabaga and spinach.

My first reaction: Berman must be misguided, mistaken. Can kale possibly be bad?

Well, yes, possibly. Here’s the science-y lowdown on the kale-thyroid connection from the Oregon State University Micronutrient Information site:

Very high intakes of cruciferous vegetables…have been found to cause hypothyroidism (insufficient thyroid hormone) in animals (68). There has been one case report of an 88-year-old woman developing severe hypothyroidism and coma following consumption of an estimated 1.0 to 1.5 kg/day of raw bok choy for several months. Two mechanisms have been identified to explain this effect. The hydrolysis of some glucosinolates found in cruciferous vegetables (e.g., progoitrin) may yield a compound known as goitrin, which has been found to interfere with thyroid hormone synthesis. The hydrolysis of another class of glucosinolates, known as indole glucosinolates, results in the release of thiocyanate ions, which can compete with iodine for uptake by the thyroid gland. Increased exposure to thiocyanate ions from cruciferous vegetable consumption or, more commonly, from cigarette smoking, does not appear to increase the risk of hypothyroidism unless accompanied by iodine deficiency. One study in humans found that the consumption of 150 g/day (5 oz/day) of cooked Brussels sprouts for four weeks had no adverse effects on thyroid function.

(For an updated reality check on kale consumption and the thyroid, see our Q and A with endocrinologist and thyroid expert Dr. Jeffrey Garber here. Bottom line: in the U.S, where we don’t have a big problem with iodine deficiency, it’s probably OK.)

Teresa Fung, Sc.D., M.S.. an adjunct professor of nutrition at the Harvard School of Public Health and a professor at Simmons College in Boston, confirms the kale-thyroid link. But, she says, “normal, reasonable amounts of eating should not be a problem. A regular person [with no thyroid issues] who eats several servings of cruciferous vegetables a week should not have problems.”

Fung adds: “It’s the dose that makes a poison. If people have hypothyroidism or they’re taking thyroid medication, then they should check with their doctor. But even in this case, reasonable amounts shouldn’t be a problem. Now, if people have a tall glass of kale juice every single day, then it gets into the unknown territory.”

So, what are still-anxious kale-lovers to do? I asked Somerville, Mass. health coach and psychology of eating coach Nina Manolson to offer some guidance. (She’s not a doctor, but she knows a lot about food, so keep that in mind and always check with a professional if you make major changes in your diet.)

Nina reiterated that kale is a goitrogenic food, meaning that it can contribute to an enlarged thyroid — a goiter. A goiter indicates that the thyroid gland is not functioning optimally. But, she says, there are ways to have our kale and eat it too. Here, lightly edited, are her suggestions:

1. Cook Your Kale

The goitrogenic properties of kale become dramatically lessened when kale — or any other cruciferous vegetable — is cooked. (Other veggies in this category include: broccoli, brussel sprouts, cabbage, cauliflower, collard greens, kohlrabi, mustard, rutabaga, turnips, bok choy and Chinese cabbage. Arugula, horseradish, radish, wasabi and watercress are also cruciferous vegetables.) Continue reading

Daily Rounds: Medicare Fraud; Hope For Hauser?; Legalizing Pot; Heavy Smoking And Alzheimer’s; Thyroid Radiation Threat

Medicare Database Offers Window Into Doctor Fraud and Abuse – WSJ.com One New York City-area family-practice doctor "pocketed more than $2 million in 2008 from Medicare, the federal insurance program for the elderly, government records suggest. That made her one of the best-paid family-medicine physicians in the Medicare system. But more noteworthy than the sum is her pattern of billing, which strongly suggests abuse or even outright fraud, according to experts who have examined her records. This doctor didn't do typical family medicine. Instead, she administered a wide array of sophisticated tests, including polysomnography sleep analyses, nerve conduction probes and needle electromyography procedures—some of which have been flagged by federal antifraud authorities for special scrutiny.” (Wall Street Journal)

Harvard Case Against Marc Hauser Is Hard to Define – NYTimes.com“The still unresolved case of Marc Hauser, the researcher accused by Harvard of scientific misconduct, points to the painful slowness of the government-university procedure for resolving such charges. It also underscores the difficulty of defining error in a field like animal cognition where inconsistent results are common.” (The New York Times)

Pot Legalization Divides California's Black Voters : NPR “Voters across California are divided on the issue of legalizing the recreational use of marijuana, but the division is especially true for black voters throughout the state. The California NAACP is endorsing Proposition 19. But some black religious leaders fear that passing the ballot measure would only hurt already struggling communities.” (npr.org)

Heavy smoking in midlife may be associated with dementia in later years “Heavy smoking in midlife is associated with a 157 percent increased risk of developing Alzheimer's disease and a 172 percent increased risk of developing vascular dementia, according to a Kaiser Permanente study published in the Archives of Internal Medicine.” (EurekAlert)

Thyroid Cancer Patients Shield Others From Radiation – NYTimes.com “One person alarmed about the situation is Representative Edward J. Markey, Democrat of Massachusetts, whose office has been studying the issue. He accuses the Nuclear Regulatory Commission of turning a blind eye to the problem. ‘My investigation has led me to conclude that the levels of unintentional radiation received by members of the public who have been exposed to patients that have received ‘drive through’ radiation treatments may well exceed international safe levels established for pregnant women and children,’ Mr. Markey said in a statement.” (The New York Times)