Eat This Newsletter 229: Milk and Memory
Today's delivery is later than usual because this is one of those issues in which I report Brand New Science, which I am not allowed to do until permitted by the journal.
I hope none of that detracts from your enjoyment of Eat This Newsletter.
“Increased milk intake associated with reduced risk of type 2 diabetes for some”
That headline on a press release from a scientific journal made me sit up and take note. Before I go into the details, though, stop for a minute and guess who the “some” might be.
Did you think for one moment it might be people who cannot easily digest milk? Me neither, and yet that is correct. People who as adults do not produce the lactase enzyme needed to digest the lactose in milk are less likely to develop type 2 diabetes the more milk they drink.
Qibin Qi and colleagues looked at the lactase gene in more than 12,000 Hispanic/Latino people and asked each how much milk they drank. Then they waited to see who developed type 2 diabetes. It turned out that an extra cup (250ml) of milk a day (but not more cheese or yoghurt) was associated with a 30% decreased risk of developing type 2 diabetes, but only in people who were lactase deficient.
Digging deeper, the gut bacteria of lactase non-persistent people contained more Bifidobacterium species and fewer Prevotella species, while their blood chemistry reflected those differences with more compounds produced by the former and fewer from the latter. The increase in Bifidobacterium species is not surprising as they thrive on milk sugars, more of which would be left for them in people who do not digest lactose, and some of the compounds produced by the bacteria are known to be protective against type 2 diabetes.
There is a lot more detail in the research paper, although one thing is clear. This research clarifies confusion surrounding some of the previous studies showing associations between drinking milk and type 2 diabetes. Among East Asian populations, milk protects against type 2 diabetes, while among white populations it is neutral or even increases the risk. Different numbers of lactase-persistent people could account for the differences.
Got More Milk
Sticking with milk, JSTOR’s daily news has a long article that briefly covers a lot of the same ground as Anne Mendelson did when we spoke last year. It does not, of course, mention the link between type 2 diabetes and lactose intolerance.
Not Got Fromage
A dearth of microbiological diversity threatens the future of some French cheeses, according to the French National Centre for Scientific Research. The story is familiar. In search of a more standardised product and more efficient production, the French cheese industry selected just a few strains of the fungi that help to mature cheeses. As a result, many of these strains can no longer reproduce sexually and, according to the research, that means they degenerate over time.
Penicillium roqueforti is still diverse enough when it comes to “proper” Roquefort, produced according to the Protected Denomination of Origin regulations. Others buy inoculant from firms that supply the whole industry, and that strain of the fungus may no longer be capable of maturing the cheese effectively. For Roquefort, help may be at hand in the form of a newly discovered strain of P. roqueforti found in Termignon blue.
A greater threat faces Camembert, which since 1902 has been inoculated with a single strain of P. camemberti. These days, the rind of all Camembert is pure white, the result of intense selection to get rid of strains that produced blue-green and even orange surface mould. The resulting strain is completely asexual and very poor at producing spores, threatening the supply of the pure cultures that cheesemakers demand.
What to do? Some cheesemakers are already using other fungi, even though the PDO for Camembert explicitly forbids the use of anything other than P. camemberti. Others want to use different species of Penicillium, which might mean putting up with the kinds of “defects” that industrial cheesemakers worked so hard to eliminate. As the article concludes:
If cheese lovers want to keep enjoying these products, they will have to learn to appreciate greater diversity in flavour, colour and texture, perhaps even among cheeses from a single source. And, who knows, thereby contribute to enriching our gastronomic heritage
Crop Diversity Trifecta
Anthropocene Magazine has a handy summary of recent research into crop diversity on the North China Plain. Bottom line: adding more crops to the current dominant rotation of wheat and maize increases yields and profits, sequesters more carbon in the soil and reduces overall greenhouse gas emissions.
The researchers added sweet potato and a legume, like soybeans or peanuts, to the rotation and at the same time reduced the amount of synthetic fertilisers applied to the field. Sweet potato is a cash crop that increased farmers incomes by about 60%. Soybeans and peanuts have a lower impact on incomes (13–22% increase) but more than compensated for lower fertiliser inputs. Not surprisingly, lower nitrogen fertiliser results in lower emissions of nitrous oxide, a greenhouse gas. What was a surprise was an increase in carbon in the soil, perhaps because diverse crops result in more diverse microbial populations which in turn trap atmospheric methane and carbon dioxide.
[D]eveloping and adopting diversified cropping systems should be a key consideration in agricultural policy setting and a top priority for on-farm decision-making.
Projecting the experimental results to the whole of the North China Plain could, the researchers say, increase cereal production by 32% and reduce the need for fertilisers by 3.6 million tonnes. That alone, they say, would reduce China’s greenhouse gas emissions by 6%. And annual farm incomes would increase by 20%.
A Forgotten Swiss Triumph
A subscriber sent me a copy of an article in the London Review of Books, and I’m delighted that they did. A National Evil, by Jonah Goodman, tells the fascinating and largely forgotten story of how a couple of country doctors came up with the theory and did the experiments that convinced a third to mount a canton-wide campaign that eventually overcame the scourge of goitre and cretinism in Switzerland. Caused by a lack of iodine, a tiny amount of that element in table salt eliminated these maladies quickly and completely.
I had been vaguely familiar with the story of iodine tablets in Akron, Ohio, published in 1917 although unknown to the Swiss pioneers, and I was equally vaguely familiar with the idea that goitre had once been a tourist attraction in Switzerland. But I had absolutely no idea that the Swiss had solved the problem independently. Jonah Goodman, in telling this fascinating story, offers some thoughts on why it is not better known. Rapid collective forgetting seems to be the answer.
The person who sent me the article shared this:
I sent it to a Swiss colleague who had no idea about any of the local characters/history, but whose mother always insisted to make sure he bought salt with iodine in it when he went to the store. Photographs of his grandmother show a goitre, and two of five kids in one family in his tiny childhood mountain village were deaf and mute.
A triumph indeed, and one that deserves a better memory.