Some nutrients, like vitamin D, always seem to be making headlines -- while others, you just never hear about.

Take choline, for example.

When was the last time you heard about that one? Possibly never -- but you might want to add it to your vocabulary, because this B vitamin found in egg yolks, liver, and chicken may have the power to protect your brain and keep dementia at bay.

Researchers looked at data on some 1,400 adults between the ages of 36 and 83 who were tracked for nearly a decade and given MRI exams along with tests to check both memory and cognitive ability.

You might want to stock up on eggs: The patients with the highest dietary choline intake did much better on those memory tests than those with the lowest. What's more, the MRIs revealed fewer signs of "white matter hyperintensity" in the brain.

That's a blood vessel problem that may be linked to both stroke and dementia.

Sounds great, right? But there's just one catch: The choline levels were calculated based on food surveys, and food surveys simply aren't good science. They rely too much on guesses, estimates, and memory.

That last one's a little ironic given that memory tests were part of the study. Can those who did the worst on those tests really be relied on to give an accurate accounting of their food intake?

On the other hand, this study doesn't come out of the blue, either -- because choline is needed by the brain to make acetylcholine, a neurotransmitter involved in everything from muscles to memory.

Some studies have shown that Alzheimer's patients lose the ability to turn choline into acetylcholine, and some promising experimental research has looked into finding ways to correct that -- although if the problem is in the conversion, then choline supplements on their own won't stop the disease.

But if they can prevent it, we're on the right track -- and earlier studies have shown that rats given choline in the womb go on to develop more powerful brains later.

Since choline is also essential for everything from your heart to your liver, you might want to add this to your supplement list. After all, it's unlikely you're getting enough from diet alone -- unless you're eating plenty of egg yolks.

By the way, choline isn't the only B vitamin that can play a key role in stopping and even reversing cognitive decline: Seniors given a blend of B6, B12, and thiamine did significantly better on memory tests and had fewer signs of the brain shrinkage linked to dementia.

Learn more here.