Here is a simple observation that, I believe, exposes a major problem in the modern diet, one that you can readily fix.
Take a look at images of people from long ago, e.g., Greek or Roman statues. Or images of indigenous hunter-gatherer populations such as the Yanomami or Hadza. Specifically notice the depth of their nasolabial folds, the skin folds that run from the nose to sides of the mouth. You may observe that, in modern people, the depth or prominence of the nasolabial folds has increased: deeper, extending further up along the nose and down to the chin.
Granted, there is substantial individual variation: Some people develop deep folds in their twenties, some have little or no such effects into their later years. But look at many images of people from the past and modern people and I believe that you will come away with the impression that, overall, the depth and length of the nasolabial fold have increased in modern times. So what?
I believe that we could argue that the deepening and extension of the nasolabial fold is just one indication that modern humans are collagen-deficient. Most people no longer consume collagen-rich organs such as tongue, heart, stomach, or intestines. We avoid tough cuts of meat filled with marbling and other forms of connective tissue. We fail to boil the carcass of animals after we have consumed the meat to mobilize collagen from tendons and ligaments.
We know from the growing experience with supplementation of collagen hydrolysates that increasing collagen intake smooths skin wrinkles by increasing the content of collagen in the dermal layer of skin, reducing wrinkle depth; increases joint cartilage volume, joint lubrication, and reduces inflammation (via inhibition of matrix metalloproteinase); reduces blood pressure; and may slow cognitive decline. In other words, restoring something lost from the modern human dietary experience restores a number of youthful characteristics.
Combine this with the effects of the oxytocin boost we get from restoring the lost keystone microbe, Lactobacillus reuteri, that also stimulates dermal collagen production, and you have a powerful synergistic combination that further reduces depth of the nasolabial fold. The Yanomami and Hadza routinely consume collagen-rich food sources, as did people in Ancient Greece and Rome. They all also harbored this ubiquitous mammalian microbe, L. reuteri, since they did not ingest antibiotics, antimicrobial food preservatives, or glyphosate. They therefore enjoyed less prominent nasolabial skin folds due to increased dermal collagen.
If you buy this line of thinking, it means that modern lifestyles deficient in collagen accelerate skin aging, joint deterioration, and perhaps cognitive decline. Restoring collagen intake, whether via consumption of fish and poultry skin; broths and stews made from the remnants of meats, poultry, and fish; or collagen hydrolysate supplementation can reverse these inadequacies. And you can track the depth of your nasolabial folds to gauge whether you are having a positive effect or not.
And, by the way, while you are looking at images of ancient people, also look at their necks to see if they have goiters. Recall that goiters, i.e., enlarged thyroid glands on the neck, were a huge public health problem all throughout human history, responsible for many deaths from progressive hypothyroidism, congestive heart failure, and compression of the airways. This remained true until 1924 with the introduction (in the U.S.) of iodized salt coupled with advice from the FDA to “Use more iodized salt; keep your family goiter-free!” Fast-forward several decades when “official” dietary advice to cut fat and saturated fat and increase grain consumption prevailed, a style of eating that increases insulin resistance and thereby sodium retention, the FDA (forgetting their original advice to increase consumption of iodized salt) urged Americans to reduce salt use. You know what follows: a return of hypothyroidism and, in some cases, goiters.
Over and over again, we learn that restoring factors lost from the modern dietary experience yields extravagant benefit, factors lost due to misguided Dietary Guidelines, the proliferation of processed foods, and human weakness.