Krispy Kreme doughnuts go into production at the opening of the store at Harrods in London, October, 3, 2003.
The consumption of fatty and sugary foods may lead to a decline in cognitive function, according to a new study. Reuters

It's the first day of June, but more importantly, it's National Doughnut Day. And that means competing donut chains Krispy Kreme and Dunkin' Donuts are both offering free doughnuts, although the Dunkin' deal comes with an asterisk. Find out how to score your free doughnut.

Krispy Kreme is offering a free donut today to anyone visiting one of the chain's 234 locations in 38 states that are participating in National Doughnut Day. Find the closest Krispy Kreme near you here.

Celebrate one of the sweetest days of the year by commemorating National Doughnut Day with a one-of-a-kind complimentary treat from Krispy Kreme, the Winston-Salem, N.C.-based company said on its National Doughnut Day Facebook page. On Friday, June 1, stop in to any participating Krispy Kreme U.S. shop for a FREE doughnut of any variety. No purchase necessary. On Friday, June 1, Krispy Kreme is helping its fans across the country pay homage on this delectable holiday by offering every guest one FREE doughnut of any variety at participating Krispy Kreme U.S. locations.

Dunkin' Donuts is also giving away free doughnuts at any of the franchise's 6,700 shops in the United States that are participating in the promotion, provided that customers buy a beverage.

Find your nearest Dunkin' Donuts to get your free doughnut on National Doughnut Day here.

Celebrate National Donut Day at U.S. DDs & enjoy a free donut w/ Dunkin' beverage purchase, the company said in a post that received more than 11,000 likes.

I am off today so I am going to see If I am going get my FREE donuts Happy Donuts day!, exclaimed Facebook user Geri C Wiese.

The country is getting swept up in National Doughnut Day, with three doughnut-related topics trending today on Twitter: Happy National Doughnut Day, #DunkinNDD, and Krispy Kreme.

Happy National Doughnut Day! Who else loves Dunkin Donuts as much as we do?, tweeted the Camp Leaders Twitter account.

National Doughnut Day is brightening up the day for Twitter user Danny Medlock.

Just had a nightmare, but then I woke up and it was Happy NationalDoughnut day. Life is good, he tweeted.

Happy National Doughnut Day!!!....I want a doughnut now..., said user @BTR1DLover.

National Doughnut Day started as a fundraiser for the Salvation Army in 1938 and is celebrated on the first Friday in June, according to punchbowl.com.