How the great coffee lie could lead to cognitive impairment

"I can drink coffee -- coffee's healthy, right?"

Every time I hear that, I can't help but be impressed by the coffee industry's publicity machine.

There are at least as many risks to a coffee habit as there are benefits (some of which are debatable), but all we ever seem to hear about in the media are stories of how it's some kind of brain-boosting, cancer-fighting wonder tonic.

So let me pour some cold water over this, and not just to make iced coffee -- because the latest research shows just how complicated it really is.

Some recent studies have found that coffee may help cut the risk of dementia and Alzheimer's disease in some people.

These are observational studies, not clinical trials, so they should be taken with a grain of salt instead of the usual teaspoon of sugar. And the new study even shows how just the opposite can also be true: While coffee can in some cases cut the risk of cognitive decline, in others it could actually increase your odds of battling this condition.

People who consistently drink a cup or two a day have a slightly lower risk of mild cognitive impairment, according to the study in the Journal of Alzheimer's Disease.

And if that's all you read, you might assume coffee is the tonic many claim it is.

But there's more to this study, which finds that the key is consistency -- because if your coffee habits change over the years, you could actually suffer from a higher risk of the very cognitive problems you're looking to avoid.

Even the smallest change in coffee habits can increase your risk.

If you normally drink a cup a day and increase it to two, your risk of mild cognitive impairment will double when compared to folks who cut back on coffee, according to the study of nearly 1,500 seniors.

So here's my advice: An occasional cup of coffee probably won't hurt you. But don't drink it because you think it's healthy -- and certainly don't drink a lot of it (and don't add sugar or flavoring syrups).

I prefer tea, especially organic green and herbal teas. They provide most of the same benefits often attributed to coffee, but without the risks.

And since herbals usually contain no caffeine, they're safe to have late in the day and into the evening.