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is the paleo diet scientific?

The paleo diet recommends eating a diet rich in meats, seafood, vegetables, fruits, and nuts while avoiding refined grains and sugars. The thinking is that the human body is best served on a diet that mimics what hunter-gatherers ate. Laura Miller argues that the diet is not scientific in Salon:

For this reason, generalizations about the typical hunter-gatherer lifestyle are spurious; it doesn’t exist. With respect to what people ate (especially how much meat), the only safe assumption was “whatever they could get,” something that to this day varies greatly depending on where they live. Recently, researchers discovered evidence that people in Europe were grinding and cooking grain (a paleo-diet bugaboo) as far back as 30,000 years ago, even if they weren’t actually cultivating it. “A strong body of evidence,” Zuk writes, “points to many changes in our genome since humans spread across the planet and developed agriculture, making it difficult at best to point to a single way of eating to which we were, and remain, best suited.”…

Furthermore, the fossil record of the Stone Age is so small and necessarily incomplete that its ability to tell us about paleolithic society is severely limited. Consider this: For all we know, the first tools were not stone implements but woven slings designed to allow a mother to carry an infant while foraging; it’s just that stone happens to survive longer than fibers.

carbon dioxide, the ocean and mussels

Mussels

Mussels.

Scientific American reports on the plight of mussels. The ocean is becoming more acidic as man-made carbon dioxide emissions continue to increase. This is having a devastating effect on mussels, making them weaker than before. From the article:

The strength of a mussel, the shellfish’s ability to grasp tightly to rocks, docks and ships despite crashing waves or prying fingers, is legendary. Scientists have even studied how mussels, using slender fibers called byssal threads that are simultaneously hard and stretchy, are able to cling so tight in a rough, wet environment, in hopes that humans could mimic that technology to create strong, flexible textiles.

Now, climate change is impairing that ability to cling. Researcher Michael O’Donnell, an ecologist at the University of Washington, has shown that ocean acidification, a process in which absorbing large amounts of carbon dioxide lowers the pH of oceans, is weakening mussels’ byssal threads.

O’Donnell and his colleagues took bay mussels from San Juan Island, in the Puget Sound, and put them in chambers with seawater at different pH levels. They found that the mussel byssal threads grown in acidified conditions with a pH lower than 7.6 were 40 percent weaker than normal. The research was published Sunday in the journal Nature Climate Change.

links

Two links for you today:

grapes

1. Have you ever wondered how they get grapes to grow so big these days? NPR explains how farmers use a technique called girdling to force the plant to grow larger fruit. This technique along with the use of gibberellic acid, which acts as a kind of growth hormone for the plant, is the reason why the size of grapes in the supermarket is ever increasing. Check it out.

Bee on flower

2. And now more on the topic of bees and flowers. Flowering plants use caffeine to lure bees. The New York Times reports on a study showing that flower nectar contains caffeine. Caffeine is a stimulant, and the flower uses it as a kind of reward in an operant conditioning mechanism. The bee gets rewarded with this stimulant drug after pollinating the flower. Having linked the reward to the smell and taste of the flower nectar, the bee searches out more of the flower. The study shows that caffeine helps increase the bee’s memory of the flower’s odor. Have a look!

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