According to a manufacturing and research business, South Dakota ranks 38th among all the states and the District of Columbia on a list measuring what researchers call brain health.

The Brain Health Index is compiled by Martek Biosciences of Maryland.

A spokeswoman says it's not an intelligence ranking but rather involves lifestyle and health.

South Dakota ranked best in the nation for people not missing work because they were discouraged, depressed or otherwise unable to function. The state also was rated fourth in community participation and seventh for social and emotional support.

But South Dakota is 44th for body mass index and No. 48 for eating - or failing to eat - five fruits and vegetables a day. The researchers say those practices hinder the brain, as does the neglect of fish.

South Dakota scored 36th in fish sales and in eating fish that contain a compound called DHA.

The study recommends a diet of salmon, trout and foods fortified with DHA.

Martek Biosciences makes DHA omega-3 products.

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