A sharper mind won't just help you ward off the signs of dementia – new research finds that keeping keen can also mean a healthier heart.

Just don't forget your fruits and veggies.

A new study finds that seniors with better cognitive abilities who eat lots of nutritious fruits and vegetables are much less likely to die of heart disease than those with poorer cognitive function who eat fewer fruits and veggies.

Drexel University researchers studied data on nearly 5,000 participants in the U.S. Longitudinal Study of Aging who were 70 or older. The study tracked dietary habits and cognitive abilities – how well we think and remember – over an average of seven years.

The researchers found that seniors who ate three or more vegetable servings each day lowered their risk of dying from heart disease by 30 percent. They also had a 15 percent lower risk of dying from anything at all during the study period than seniors who ate less than three daily veggie servings.

The study also found that higher consumption of fruits and vegetables led to much better scores on cognitive tests.

And the participants who did the best on cognitive tests – regardless of how much fruit and vegetables they ate – were less likely to die from any cause, including heart disease, during the study period than those who did poorly on those tests.

So you can see what's happening here – it's the opposite of a vicious cycle.

Seniors eat fruits and vegetables. Those healthy foods helped keep their minds sharp by providing their bodies with the nutrients their brains need most. And those sharper minds rewarded them with healthier hearts.

Staying sharp can mean any number of things – just be sure to keep all the cylinders in your brain firing by challenging yourself every single day. Whether it's a book club discussion or a game of "Boggle," a puzzle or a piano lesson, exercise your mind like you would any of your muscles – there's a very real possibility that you'll lose it if you don't use it.

Then, make sure you eat right – a side of vegetables with every meal will make sure you get those three minimal servings daily, and you can eat even more than that when it comes to these healthy foods.

Be a little more careful when it comes to fruit because of the high levels of natural sugar – but make sure you some of those every day, too – from berries to bananas, fruit is a great natural source of so many necessary nutrients.

And finally, be sure to get some exercise every day. One new study found that the hearts of seniors who've been exercising for years look much younger than those of seniors who haven't. The best results were in those who had been exercising longest – so get started now.

But exercise, food and cognitive abilities aren't the only ways to keep your heart healthy.