species: fish

A Whale of a (Milk) Tale

A Whale of a (Milk) Tale

Blue whales, along with other species of baleen whales, are remarkable for their ability to put on massive amounts of blubber during pregnancy. What may be even more remarkable, however, is their ability to quickly transfer that stored energy to their developing calf during lactation, all while consuming little, if any, food. But not all whales share this intense lactation strategy. The toothed whales (the evolutionary "cousins" of baleen whales) are the tortoise to the baleen whales' hare, taking the slow and steady approach to milk production that is reminiscent of humans and other primate species. Why don't the baleen whales pace themselves a bit more? Or, alternatively, why don't the toothed whales pick up some speed? The evolution of two such dramatically different strategies in these closely related marine mammals can only be understood in the context of the species' entire life course. After all, evolutionary success is not about winning a sprint, but successfully playing the long game. Read More...

Getting the Balance Right

Getting the Balance Right

Once described as an epidemic, obesity has now reached pandemic status with an estimated 600 million obese adults worldwide, and an additional 1.4 billion that are overweight. The cause of the pandemic is known—people consuming more energy (calories) than they expend—so it would seem that the solution would be to simply eat less. But a team of nutritional ecologists believes that cutting calories will not solve anything, because it ignores some basic tenets of human (and animal) biology. Using data from fruit flies, mice, birds, fish, monkeys, and humans, Raubenheimer, Simpson and their colleagues demonstrate a seemingly universal law of animal nutrition: a predominant appetite for protein. They propose that the human need to meet a fixed daily protein target leads to weight gain through the overconsumption of low protein foods that have come to dominate the Western diet. Rather than advocating for a high protein diet that eschews carbohydrates, they emphasize a balance of macronutrients for optimal health. Can dairy help strike this balance? Whole-food sources of protein that are easy to access, like dairy, can help balance out those beloved low-protein, high-carbohydrate processed foods and keep energy consumption in check. Read More...

A Tale of Fats, Fish, Dolphins, and Dairy

A Tale of Fats, Fish, Dolphins, and Dairy

For decades, we have been warned about the evils of saturated fats in our food. We have heard that this whole “family” of fats increases our “bad cholesterol,” and hence increases our risk of cardiovascular and metabolic diseases. Recently, however, this widely accepted mantra has been challenged by growing evidence that some saturated fats, such as milk fats, do the exact opposite: they appear to reduce our risk of many diseases, including type 2 diabetes. While scientists debate the mechanisms involved, the changing view on saturated fats is underpinned by a new study of some unexpected contenders: dolphins (1). Read More...

How Much DHA Should Be in Human Milk?

How Much DHA Should Be in Human Milk?

The goal of infant formula is to mimic breast milk composition. When considering milk components that vary widely across and within populations, whose breast milk should be used as the gold standard? For example, the breast milk concentration of DHA, a long-chain polyunsaturated fatty acid implicated in brain growth and development, is influenced by DHA in the mother's diet, and diets vary among populations. Read More...

The Evolutionary Origins of Milk Letdown

The Evolutionary Origins of Milk Letdown

The production of milk by the mammary gland is a key adaptation of mammals. But simply producing the milk is not enough; that milk needs to get from the mammary gland to the nipple to be ingested by the infant. But how is this movement of milk accomplished? An amazing hormone called oxytocin. How did oxytocin, and therefore milk letdown, it evolve? Read More...