Head out to the garden early in the morning and pull a handful of Swiss chard, kale, and spinach. The darker the leaf, the deeper the green stain left on your fingertips. And there's a new piece of research suggesting that the vitamin K packed into those dark leaves may be tied not only to bone health, but to the mind as well.
The Vitamin K in Dark Leaves
Vitamin K shows up generously in deep-green leafy vegetables — kale, spinach, Swiss chard, mustard greens, broccoli, garlic chives. Its long-established jobs are helping blood clot at a wound and helping keep bones dense. What we get from leafy greens is mostly the form called K1; fermented foods like natto and doenjang (Korean soybean paste) supply K2. A single chard or kale plant will hand you leaves all summer long — enough for several dinners in a row — so getting your share takes very little effort.
A Thread Leading to the Mind
One study followed 607 older adults in a Japanese community. About one in five of them were experiencing depressive symptoms, and that share ran higher among those eating the least vitamin K. After evening out factors like age, sex, and exercise habits, the group eating the most vitamin K had depressive symptoms at roughly half the rate of the group eating the least. Vitamin K is also known to play a part in building the material that sheathes nerves in the brain, which hints at how the two might be connected.
That said, the study looked at diet and mental state at a single point in time, so it's too early to declare that vitamin K prevents depression. People who eat well tend to move more and keep steadier routines, after all. The researchers themselves noted that more work is needed. Even so, the broader direction — that a table with dark leafy greens on it regularly does good for both body and mind — isn't far off the mark.
Getting Your Greens from the Garden
Vitamin K absorbs best in the company of fat. Blanch spinach or chard briefly and dress them with toasted sesame oil. If your kale leaves have turned tough, a quick sauté in olive oil will soften them right up. Garlic chives make a generous meal folded into a savory pancake (jeon) or tossed as geot-jeori, a quick fresh-kimchi salad. On rushed mornings, a few kale leaves blended with seasonal fruit works just as well. Rather than loading up all at once, aim for one plate a day and keep those dark leaves coming.
- Blanched and dressed: briefly blanch spinach, chard, or mustard greens and toss with toasted sesame oil
- Sautéed: give tough kale a light turn in olive oil
- Pancakes and quick salad: garlic chives, enough to fill out a meal
One thing to watch. If you take blood-thinning medication, a sudden change in how much vitamin K you eat can throw off how the drug works. Talk with your doctor before making a big jump in leafy greens.
Tonight, set a plate of dark leafy greens from your garden right in the middle of the table.
