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A Healthy Diet May Help The Brain Age Well, Study Finds

A new study finds that the healthier we eat over the years, the better shape our brains will be in as we age. In the new research from McMaster University, people from all over the world who kept a Mediterranean-style diet in middle age had a reduced risk of cognitive decline as they got older. What was the magic food? There wasn’t one, and the study didn’t try to find one. Much like other areas of health, it’s not one thing – it’s a combination of things. And that’s true whether we’re talking about body health or brain health.

The team tracked the health and habits of almost 28,000 people, 55 and over, who were taking part in two international studies across 40 countries. The team rated how healthy each person’s diet was overall: Healthy diets tended to consist of higher quantities of vegetables, fruits, fish, nuts, soy products, and moderate alcohol intake. The unhealthy foods were things like red meat, deep-fried foods, and sweets.

By the end of the nearly five-year study, 4,700 people had begun to experience cognitive decline. Of the 5,700 people with the healthiest diets, 14% had developed cognitive decline. And of the 5,460 people with the least healthy diets, about 18% of them experienced cognitive decline.

It may not sound like a big difference, but it’s about a 24% reduction in risk for the healthy-diet-keepers. And extrapolating to the millions of Americans who experience cognitive decline without dementia, which is more than 5 million, eating differently might save a great many people from developing it. Globally, the effects are even more profound.

The important takeaway is that it’s not any one food that protects the brain, it’s the whole symphony of foods working together. Study author Andrew Smyth tells me, “the consumption of ‘healthy’ choices may be beneficial, but the effect may be lost/reduced with the consumption of ‘unhealthy’ choices. For example, the beneficial effect of fruit may be lost if prepared with high amounts of fats or sugars. Our data suggest that an overall healthy diet is more important than the consumption of any one particular food.”

In other words, you can’t eat a plate of kale for lunch and deep-fried fish and chips for dinner and think you’re safe. Kale is good, but it isn’t that good.

Happily, the study isn’t the first to link diet and cognitive decline. Others have shown that Mediterranean diets – very similar to the type of diet that was considered healthy in the current study – are linked to reduced risk of cognitive decline, and even of developing dementia.

And the new research is one of a growing number that shows that, more generally, the choices that we make for ourselves across a lifetime greatly influence how well or poorly our brains age. Even if a person is genetically predisposed to develop cognitive decline or dementia, it’s not written in stone – lifestyle choices matter. Other factors like regular exercise have also been linked to reduced risk of cognitive decline, and even of Alzheimer’s disease. More recently, meditation, which research has shown to change the brain, structurally and functionally over time, has also been linked to a better preserved brain with age, and even the reduction of mild cognitive impairment. And of course, healthy diets, rich in antioxidants from the super foods – blueberries, cocoa, and dark leafy greens – and in healthy fats from salmon and olive oil, are excellent for the brain and for overall health.

Since the brain is our most important organ, it’s only natural that we should feed it well. But it’s nice to have more and more studies that confirm it.

CalWater 2015 targets atmospheric rivers off California

Meteorologists investigate airborne jets that bring both floods and drought relief.

· Alexandra Witze

20 January 2015

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Darren Jackson/NOAA ESRL

A satellite image showing water-vapour concentration reveals an atmospheric river (yellow) streaming northeast across the Pacific Ocean.

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Californians call it the Pineapple Express: a weather pattern that zips across the Pacific Ocean from Hawaii, delivering not baskets of tropical fruit, but buckets of rain and snow.

In meteorological terms, the Pineapple Express is an atmospheric river, a narrow band of air that carries huge amounts of moisture. For the next six weeks, meteorologists will be plying the eastern Pacific by air and sea, in the hope of catching several atmospheric rivers barrelling towards the coast. It is the biggest push yet to understand these phenomena, which have received serious scientific attention only in the past decade.

Atmospheric rivers get their start over warm tropical waters; they then flow eastwards and towards the poles a kilometre or two above the ocean surface. They may stretch for thousands of kilometres, but are only a few hundred kilometres wide. When they hit land, they start to drop their moisture in torrential downpours or blizzards.

“When we have too many atmospheric rivers, floods can occur, and when we don’t have enough we gradually fall into drought,” says Marty Ralph, a meteorologist at the Scripps Institution of Oceanography in La Jolla, California, and a leader of the field campaign.

In Europe, atmospheric rivers affect mostly the western part of the continent, but they can be felt as far inland as Poland. In North America, the entire west coast is affected, and parts of the central and eastern United States occasionally feel the effects of atmospheric rivers that develop over the Gulf of Mexico. The moisture is often welcome, bringing up to half of the year’s water supply in affected areas¹. A 2013 study found that as many as three-quarters of all droughts in the Pacific Northwest between 1950 and 2010 had been brought to an end by atmospheric-river storms². California has been stricken by drought for years (see Nature 512, 121–122; 2014), but last month, an atmospheric river dropped enough rain to erase one-third of the water deficit of one major reservoir in just two days.

Climate change may bring stronger and more frequent atmospheric rivers, because the warmer the atmosphere is, the more water it can hold, says David Lavers, a meteorologist at Scripps who is not involved in the project. “The more you know about how the atmosphere behaves,” he says, “the better position you’re in to prepare for extreme events.”

The current US$10-million field campaign, called CalWater 2015, is a massive push to capture the physics of atmospheric rivers as they make landfall. A research vessel from the US National Oceanographic and Atmospheric Administration (NOAA), the Ronald H. Brown, is sitting several hundred kilometres off the California coast, waiting to position itself beneath an atmospheric river whenever one forms. The ship carries a suite of instruments operated by the US Department of Energy (DOE) that will peer upwards to study aerosol concentrations and other properties of the atmosphere once a river has formed.

Four aeroplanes — two belonging to NOAA, and one each to the DOE and NASA — will fly directly into the atmospheric river. They will release dropsondes, miniature parachutes carrying an array of instruments that record weather data as they descend.

One major goal is to work out how aerosols affect atmospheric rivers, says Kimberly Prather, an atmospheric chemist at Scripps and another leader of the project. A smaller field campaign in California between 2009 and 2011 suggested that contrary to expectations, aerosols served as nuclei for ice crystals to grow within atmospheric rivers and later produce snow³. “It’s Mother Nature’s way of seeding things,” says Prather.

CalWater 2015 will measure how aerosol particles interact with atmospheric rivers, both offshore and when they reach the coast. Supercomputer simulations will examine how airborne dust affects the amount and type of precipitation that eventually falls, says Ruby Leung, an atmospheric modeller with the Pacific Northwest National Laboratory in Richland, Washington.

That information should help water managers to predict what atmospheric rivers may bring. Reservoir engineers in northern California typically release precious water from their reservoirs in the winter, so as to have enough space behind the dam to cope with the threat of flooding. With better knowledge of when atmospheric rivers might arrive and how much water they might carry, says Ralph, engineers should be able to manage that winter release more effectively.

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