“Be sure to eat your sulfur.”
When’s the last time someone told you that? Except for the Wahls talk, probably never. My mother certainly didn’t.
Few people even know much about sulfur besides the whole rotten egg, fire and brimstone thing. It’s a mineral with a role in our physiology, but it doesn’t showboat like the obscenely corporeal calcium, forming bones and teeth that you can literally feel and see. It won’t immediately soothe your restless muscles or put you right to sleep, like magnesium. Unlike zinc, it doesn’t figure prominently in the production of a sexy hormone like testosterone. And though you can take iodine and get an instant reaction from your thyroid, taking sulfur doesn’t produce anything tangible. In short, sulfur lurks in the background and keeps a low profile.
So why does Terry Wahls promote the consumption of three cups of sulfur-rich vegetables every day?
Before we get to that, let’s define what we’re discussing here. What exactly qualifies as a sulfur-rich vegetable? Any and all fibrous non-leafy (although some have leaves, they’re never the culinary focus) usually-green vegetables that steam well and emit a distinctive, offensive-to-some odor probably contain considerable amounts of sulfur and can be called “sulfur-rich”:
- Brassicas – cabbage, broccoli, cauliflower, Brussels sprouts, bok choy, and related vegetables.
- Alliums – onions, shallots, garlic, leeks.
- Lots of edible stalks, lovely smells if you cook it wrong, and a tendency to go well with lemon butter. That sort of thing.
Back to Wahls’ recommendation to eat more sulfur. What’s the justification for it?
Well, by weight, sulfur is one of the most abundant mineral elements in the human body, coming in at around 140 grams for the average person. And as any regular reader of this blog should know, you don’t get to be an abundant mineral in human physiology by accident. Nope: sulfur is involved in hundreds of physiological processes. Let’s explore some of the big ones:
Sulfur is required for the synthesis of glutathione, one of our premier endogenous antioxidants. I’ve talked a bit about glutathione before. It’s one of the good ones.
Sulfur, in the form of disulfide bonds, provides strength and resiliency to hair, feathers, and feathered hair.
Sulfur is required for taurine synthesis. Taurine is essential for proper functioning of the cardiovascular system, our muscles, and the central nervous system.
Sulfur binds the two chains of amino acids that form insulin. It may seem like we bag on insulin a lot, but it’s absolutely necessary for life.
There are two reasons, I think, for focusing on “sulfur-rich” vegetables. First, it’s helpful to group things. We’ve got the leafy greens, we’ve got the brightly colored produce (more on this next week), and we’ve got the sulfurs. We want to eat things from all three categories, and making the latter a separate group ensures that we won’t “overdose” on spinach. It’s just a neat, slick way to get the pro-vegetable message across and increase variety of intake. Second, and most importantly, sulfur-rich vegetation tends to come with extremely potent organosulfur compounds that offer a lot of benefit to those who eat them. Animal sources may contain plenty of sulfur-rich amino acids, which we undoubtedly require, but they don’t contain the organosulfur compounds.
Let’s explore them and go over a few of their potential benefits.
Alliums and Their Allyl Sulfur Compounds
Garlic, onions, shallots, and leeks all contain various organosulfur compounds, some of which show major potential.
Garlic-derived organosulfur compounds have shown promise as anti-cancer operatives in in vitro studies.
Various garlic sulfides protected mice from peroxidative damage and increased glutathione activity in the liver. The garlic sulfides were delivered via corn oil, but I would recommend garlic butter if you’re looking for a fatty vessel.
When cooking meat, using an onion and garlic-based marinade reduced the formation of heterocyclic amines (a carcinogenic compound).
Onion-derived sulfur compounds improved the glucose tolerance of diabetic rats (but garlic-derived compounds did not).
Brassicas and Their Various Organosulfur Compounds
Sulforaphane, an organosulfur compound found in broccoli (especially the sprouts), cabbage, brussel sprouts, and cauliflower, inhibited mitochondrial permeability and reduced oxidative stress by increasing glutathione activity in rats.
In inhabitants of a Chinese farming community, where airborne pollution is high and liver cancer incidence is elevated, drinking a sulforaphane-rich broccoli sprout drink was also able to increase the urinary excretion of those airborne pollutants.
Broccoli sprouts reduced oxidative stress in type 2 diabetics, as shown in a double blind placebo-controlled trial.
Organosulfur compounds from all kinds of brassicas have the potential to reduce or counteract the carcinogens derived from high-heat cooking.
Eating brassicas along with a carcinogen salad prevented the absorption of said carcinogens.
How to Prepare These Vegetables (and Preserve Their Compounds)
You can’t just go eat a head of cabbage like an apple, or throw together a lovely salad of raw onion, raw garlic, and raw broccoli stalks. I mean, you could, but it’d be pretty unpleasant. No, you want to cook these vegetables, because they taste better and are likely more nutritious that way. But you also don’t want to miss out on all the delightful organosulfur compounds we’ve been discussing. You want the optimal prep method – or close to it.
Onions and Garlic
If it’s beneficial allyl sulfur compounds you want to consume, eating your alliums raw and sliced is the ticket. Heat breaks down the compounds. The only problem is that those same allyl sulfur compounds that might fight cancer, boost antioxidant status, and ward off liver damage are the very things that make raw onion and garlic so pungent and unpalatable. Some people enjoy the stuff raw – not me, besides a little chopped garlic in my salad dressings and some raw onion on a salad – but most prefer them cooked. Luckily, studies suggest that by slicing your alliums and letting them sit for at least ten minutes before cooking, you allow the myrosinase enzyme to release more allyl sulfur compounds and make them more resistant to heat.
Steaming is the way to go. One study found that lightly steaming broccoli rendered the sulforaphane three times more bioavailable than after heavily cooking it. I like to steam my broccoli until it’s bright green and tender enough to pierce the stalk with a fork with an emphatic push. Soggy, dull green broccoli is the worst – and it’s not nearly as beneficial. One group of scientists corroborate my method, saying that three to four minutes of light steaming – until “tough-tender” – is ideal.
Again, research confirms that lightly steamed cabbage offers more bioavailable organosulfur compounds than cabbage cooked at high heat in the microwave. Chop it up to your desired consistency. Let sit for a few minutes so the myrosinase gets to work. Stick to four or five minutes of steaming. Then, toss with your fat of choice. If you want to microwave, use the low or medium setting.
Cut into small florets, let sit for ten minutes (to let the myrosinase enzyme do its work and make the glucosinates more available), and steam or bake. I’m a big fan of baked cauliflower tossed with turmeric, curry powder, cayenne, salt, and olive oil.
Although I’m sure the “best” way to cook sprouts (like all the other brassicas) is to quarter and steam them for five minutes, I can’t help but think you’re missing out on the perfect opportunity for some prime caramelization in the oven. So yeah, I’ll steam Brussels sprouts and toss with butter or olive oil and enjoy them just fine, but every once in awhile I’ll finish those suckers off in the oven on high.
Slicing, sitting, and steaming is always a safe bet.
For all these foods, try to embrace the bitterness. Love the bite, because that bite and that bitterness means you’re getting those interesting compounds. Enjoy the crispness of lightly cooked brassicas from time to time. It may take some getting used to, and you might have to play with different flavor combinations so that the bitterness will work, but you’ll be pleasantly surprised. Avoid the mush.
As I mentioned in the greens post, three cups a day are probably unnecessary. Just try a bunch from the ones I’ve listed, see what you like, and try to get some sort of sulfur-rich vegetable into your mouth at least a few times a week. Or, go all out and give the three cups a day routine a shot. You might really like it and thrive on it.
What’s your favorite sulfur-rich vegetable? How do you eat it? Let me know in the comment section!