I haven't posted on this blog in a long time for various reasons, one of which is that I have been helping my good friend Danny Albers with his facebook page Primal North. Primal North and Mostly Meat Is What I Eat have a very similar view on nutrition, and the two of us have improved each others diets and dietary views through the many conversations I've had with Danny over the last several months. One change I've made is cutting out starches and vegetables, making 'Meat Is Almost All I Eat' as it were, and Danny has started putting gelatin in his coffee.
One topic we discussed was my theory about the truth behind Paul Jaminet's 'glucose deficiency'. Jaminet says that when we was eating a zero carb diet (except he wasn't as he doesn't consider vegetables as calories sources and thus counts what everyone else would call a low-carb diet a zero-carb one), that he experienced several problems including dry eyes, constipation, and a dry cough. Jaminet even claims that people die of starvation because of the dry cough they develop: "A clue is the fact that starving people develop a hacking cough in their final weeks of life. Despite blood glucose levels in the normal range, they cease producing mucus and their airways become dry and irritated." This is contrary to the well known general cause of death in starvation, which is heart failure. Everyone knows during prolonged starvation your muscle start to waste away, but it's not just your biceps that get eaten, eventually your body starts using the heart (which is a muscle) as well, ultimately the heart becomes so weakened it can't pump blood and you die of heart failure.
Danny rightly points out that a dry cough may be a cause of death in starving people due to a lack of mucous, but that that is in starving people, nutritional ketosis and starvation are vastly different. Yes, both have increased blood ketones and a lack of dietary carbohydrates but that is where the similarities end. A low/zero-carb diet producing nutritional ketosis includes protein, plenty of fat for fuel, vitamins, and minerals. We don't know if this 'dry cough = death' thing is from lack of carbohydrates, protein in general or specific amino acid(s), calories, a vitamin, or mineral. Unless properly tested we may never know, but it's unlikely such studies will ever occur in humans due the the 'death' factor, and animal testing may not be applicable.
Jaminet's answer, which is has stuck heavily too even to the point of declaring ketogenic diets outright dangerous, is lack of carbohydrates. But he even posts this picture showing the glycogen is fully depleted after just 3 days of fasting/starvation. If a lack of carbohydrates where the cause, then one would expect the problems to occur much much sooner, not the final few days of life.
My theory, which I'm fully stating that I do not know to be true but from talking with other people and seeing the difference after they add gelatin to their diet (which is the exact same level of evidence Jaminet has for his 'glucose deficiency' theory, except he states it as outright truth not as a theory, which it is), is that is it not a glucose deficiency but a mucous (or more specifically mucin) deficiency caused by an imbalanced amino acid profile.
Mucin is a glycoprotein, this means it's part carbohydrate ('glyco' as in glucose), and part protein. Jaminet has focused in on the 'glyco' part, I have explored the 'protein' side of things. In my research I discovered that mucin production is highly sensitive the the availability of certain amino acids: cysteine, proline, serine, and threonine. Cysteine is an essential sulphur-containing amino acid, which meat and eggs are very rich in. Proline is a conditionally essential amino acid, which along with glycine makes up most of gelatin. Serine is a non-essential amino acid which is made from glycine. Glycine and proline are very low in meat, fish, organs, dairy, eggs, and vegetarian protein sources; the only decent source is gelatin. Threonine is an essential amino acid, and meat, fish, eggs, and dairy are good sources. On a diet where the protein only comes from meat, fish, eggs, or dairy, there is plenty of cysteine and threonine, but very little glycine and proline.
Gelatin can be found in many foods, not just powdered gelatine like for making jelly/jell-o, in fact about
The paleo community has made many improvements over the years, from lean meat to fatty, and more decently the addition of organs such as liver, but is still lacking in the encouragement of making and using home-made gelatinous broth. This is one thing Ray Peat gets right (see here), but both Danny and I very much disagree with his promotion of eating large amounts of refined white sugar.
Please note: all store-bought 'broth', 'stock', and bouillon cubes are nothing like real home-made broth, they are made from flours, salt, MSG, and many other chemicals. There is no substitute for the real home-made stuff.
I also encouragement the inclusion of egg shells along with bones and gelatin sources in broth, as egg shells help boost the calcium content and the membrane includes chondroitin which is also very good for joints.
Lastly, I will point out that there are many factors other than a proper amino acid profile in maintaining moist mucous membranes, such as vitamin A (retinol), saturated fats, choline, cholesterol, and many others. Retinol (true vitamin A) deficiency results in mucous-secreting cells mutating into keratin-secreting cells which results in lesions being formed, in the eye this leads to xerophthalmia and eventually keratomalacia and blindness. Saturated fats are need to form surfactants in the lungs which reduce surface tension so gas exchange can happen, the most common surfactant is dipalmitoylphosphatidylcholine, made from choline and two palmitic acids (a saturated fat); cholesterol also makes up part of the surfactants.
You'll notice that all the nutrients listed for maintaining mucous membranes are only found in animal foods (there is some palmitic acid in palm oil though) so it is highly unlikely that a problem involving mucous membranes results from a lack of plant foods in your diet. Much more likely is that it results from an imbalanced intake of certain animal foods over others, that is too much meat and not enough gelatin.