Here's another reason to eat your veggies: A new study suggests certain vegetables like broccoli and spinach may help older women keep their brains sharper. 

Researchers found that women in their 60s who ate more cruciferous and green leafy vegetables than other women went on to show less overall decline over time on a bundle of tests measuring memory, verbal ability and attention. 

Such foods include broccoli, cauliflower, romaine lettuce and spinach. 

The federally funded study didn't include men, but the effect would probably appear in them too, said Jae Hee Kang, an instructor at Harvard's Brigham and Women's Hospital in Boston. 

She spoke in a telephone interview before presenting the work Monday in Philadelphia at the International Conference on Alzheimer's Disease and Related Disorders. 

Other studies released Monday showed evidence that obesity, high cholesterol and high blood pressure can raise the risk of developing Alzheimer's or other dementia later on, and that leisure activities with mental, physical and social aspects may reduce the risk of later dementia. 

Kang's study and the other two "add to the growing understanding that we may be able to reduce our risk of Alzheimer's by changing our lifestyles - losing weight, changing our diets and staying mentally and socially active," said Marilyn Albert, who chairs the Alzheimer Association's Medical and Scientific Advisory Council. 

Kang stressed that her findings need to be confirmed by further studies. 

She and colleagues looked at 13,388 nurses participating in a long-running health study. They compared the participants' questionnaires on long-term eating habits over a span of 10 years, when they were in their 60s, to their performance in two test sessions when they were in their 70s. Researchers noted how much the scores declined in the two years between sessions. 

The tests included such tasks as remembering word lists after 15 minutes, naming as many animals as possible in one minute, and reciting a list of numbers backward. A pronounced drop in performance on such tests may foreshadow Alzheimer's. 

While most women in the study showed some decline, those who had habitually eaten the most of the green leafy vegetables showed less decline than those who ate the least, Kang said. 

"It was almost like they were younger by one or two years in terms of their cognitive declining," Kang said. 

The contrasts appeared between those who ate about eight servings versus three servings of green leafy vegetables a week, and those who ate about five servings versus two servings of cruciferous vegetables a week. 

One of the other new studies found evidence that obesity, high cholesterol and high blood pressure in middle age each added substantially to the risk of developing Alzheimer's or other dementia later on. Each problem roughly doubled the risk, and study participants with all three traits ran six times the risk of somebody without any of them, said researcher Dr. Miia Kivipelto of the Karolinska Institute in Stockholm. 

Her study included 1,449 Finns whose body-mass index, which signals obesity, was calculated when they were around 50 years old. When examined an average of 21 years later, 61 had developed dementia, mostly Alzheimer's. 

Results showed the risk of any dementia or Alzheimer's in particular roughly doubled with a BMI of more than 30 (considered obese), cholesterol of more than 250 or a blood pressure reading in which one of the numbers exceeded 140. 

The effect appeared in both sexes, though the obesity factor was slightly stronger in women, Kivipelto said.