In a previous post, Blood analysis I: important numbers, I made a list of tests that would give a good idea of the state of health of the body. Many of them are part of standard or routine blood work, others are not. I personally find it both interesting and useful for everyone to monitor health in this objective, quantified manner by getting regular blood analysis once per year under normal circumstances, and more frequently if we are either critically ill or simply interested in documenting the evolution of the numbers that reflect the state of our health, especially during a transition period of metabolic adaptation such as a switch from a regular high carb diet to the ketogenic/alkalising diet. Either way, there are a few tests that I would argue are more useful than others, and therefore more important—essential even—for the purpose of monitoring your health.
Having these tests done and getting the results back is of little use if we don’t understand what they mean. So, I first list a minimal set of fasting blood tests to do either by themselves or in addition to those commonly done, and explain their relationship to the state of our metabolism and physiology.
- Insulin to be as low as possible (mine is 2-3 mU/l)
- Glucose to be as low as possible (mine is 70-80 mg/dl, and I don’t eat carbs)
- Triglycerides to be as low as possible (mine are 35-50 mg/dl)
- Urea and Uric Acid to be as low as possible (mine are ~20 and ~5 mg/dl)
- C-Reactive Protein to be as low as possible (mine last one was < 0.1 mg/l)
- Creatinine to be between 0.5 and 1 mg/dl (my last one was 0.72 mg/dl, and I exercise daily and do weights)
- Vitamin D3 25OH to be above 50 and below 100 ng/ml
- Vitamin B12 to be never below 600 and between 600-2000 pg/ml
The first three—insulin, glucose and triglycerides—give you a very clear picture of metabolic efficiency: of how well your cells use glucose and fat. Optimal metabolic efficiency is when cells use fat as their primary source of fuel. But when stress hormone levels rise while lifting a heavy weight or sprinting, and glucose is synthesised from the glycogen in the muscle or/and in the liver and released into the bloodstream, then cells use it very efficiently. If under certain circumstances glucose levels rise and remain somewhat higher for a while, a very small amount of insulin is needed, and therefore secreted, because all cells, especially those in the liver, muscle and fatty tissues, have exquisite insulin sensitivity.
It is important to measure both glucose and insulin because in most normally “healthy” people, as insulin resistance grows over time, the pancreas adapts and secretes more and more insulin. Levels of glucose can remain relatively low, i.e., in the “normal” range < 110 mg/dl, but only because insulin levels are higher. Higher insulin levels cause further and faster increase in insulin resistance, which continues to require greater amounts of insulin from the pancreas.
Since insulin concentration is probably the best indicator of health and longevity in practically all living creatures, simple and complex, obviously including humans, you want to have it as low as possible. To have insulin as low as possible, glucose needs to be as low as possible. And for glucose to be as low as possible, we need to eliminate simple and starchy carbs from our diet, and establish and maintain nutritional ketosis in which fat is used continuously as the cellular fuel of choice, which it is. (For more details you can read my earlier posts We were never meant to eat simple or starchy carbohydrates, and When you eliminate insulin-stimulating carbohydrates).
Triglycerides are fats: three fatty acids attached to a backbone of glycerol. When metabolic efficiency is high and fat utilisation good, triglycerides are low because they are easily used by the cells. If, on the contrary, metabolic efficiency is low and fat utilisation poor, then triglyceride concentrations will be high. The lower their concentration, the higher the metabolic efficiency and fat utilisation. That’s what we want for optimal health and long life, and keep in mind that fats cannot be used while insulin levels are high.
Urea and Uric Acid give you a good idea how much acidity is circulating in the blood in relation to how much protein you eat, because they are both bi-products of protein metabolism and digestion, and are both excreted by the kidneys into the urine as waste. Urea results from the oxidation of animo acids ingested from food and not used for the synthesis of proteins and other biological substances; in other words, from a surplus of ingested protein. It is the primary metabolic waste that finds its way out of the body through the urine. Urea is also used by the kidneys in order to increase reabsorption of water in case of dehydration. Uric acid results from the final oxidation (breakdown) of purine, which is found mostly in protein-rich animal foods, and, like urea, is excreted in urine. Both need to be as low because unexcreted excesses of either will force the body to store them as urate crystals in the tissues, preferentially in the joints but also throughout the body. This leads to the gradual growth of tissue acidosis, which is the root cause of a very wide spectrum of problems. Keeping these acidic waste products low is done through consuming only the minimum required amounts of protein (0.5-0.75 g/kg/lean mass/day), eating and drinking to alkalise—not acidify—in order to maximise their excretion through the urine, which cannot be done without excellent hydration and adequate salt intake. (More details in How much salt or how much water? and in Treating arthritis I).
C-Reactive Protein is one of the best indicator of systemic inflammation, and systemic inflammation is common and maybe even at the root of all degenerative diseases, including atherosclerosis and heart attack, stroke and Alzheimer’s, arthritis and multiple sclerosis, and on and on and on. Therefore it is very simple: you want the minimum amount of inflammation in your body, and obviously, the minimum amount of the tracers of inflammation, of which C-Reactive Protein is very reliable. (Interleukin-6 is another good one.)
Creatinine is related to muscle energy metabolism and muscle tissue breakdown. It is a metabolic waste that also needs to be excreted by the kidneys. For example, body builders have very high levels of it because they are continuously breaking down muscle fibres through weight training, but their body is also rebuilding and, in fact, building more muscle mass as a result of the training. So that is perfectly normal in their circumstances. If you are not a body builder, then your levels of creatinine should be relatively low.
It is important to point out that insulin resistance leads to muscle breakdown for the straight-forward reason that high levels of insulin prevent fat breakdown, and when glucose levels drop and glycogen stores are low, the body will break down muscle to make glucose out of it in order to supply a source of fuel to the cells. Any level of insulin resistance will cause muscle breakdown in these circumstances, which, for most people is every night, and during any period of fasting for longer than a few hours. The more insulin resistant, the more the amount of muscle breakdown. So, as the metabolic efficiency grows with time while nurturing nutritional ketosis, insulin sensitivity grows, fat utilisation grows, muscle breakdown decreases, and creatinine levels drop.
Looking a little further, we find that cholesterol lowering statin drugs have the awfully negative side-effect of causing muscle tissue breakdown. And so, people taking such medications—which absolutely nobody should—typically have much higher levels of creatinine production. At first, starting with relatively healthy kidneys, it is not noticed because most of it is cleared from the bloodstream and excreted. Over time, however, the continual stress on the kidneys causes irreparable damage to the fragile filtering nephrons, and creatinine levels in the blood start to rise. Eventually, this can—and much too often does—lead to kidney failure. If the person does not die from it, they will, for the rest of their lives, depend on regular dialysis or on a kidney transplant for long term survival; “long term” here means more than a few days. So, stay away from cholesterol-lowering drugs, no matter what your doctor says.
Vitamin D3 (25-OH-D), which must be optimised because so very many cellular, hormonal and metabolic processes depends on this fat-soluble pre-hormone, and must be monitored because there are very important differences in the needs of different individuals primarily due to their genetic background. For optimal health, it is essential to monitor vitamin D concentrations at least on a yearly basis (at the start of the winter), if not every half year.
Vitamin D is either consumed in certain fatty foods, or produced by the interaction of solar UV-B rays on the skin. Production of vitamin D strongly depends on cholesterol levels that must be optimally high (between 200 and 240 mg/dl), and once produced, requires 24-48 hours to be completely absorbed into the bloodstream. Therefore, if you wish to absorb the vitamin D produced on your skin, you should not wash with soap after sun exposure to the midday sun in the summer; it is only at midday when the sun is at the zenith that UV-B rays can pass through the atmosphere and reach the surface. Without UV-B there can be no vitamin D synthesis.
So, in the summer you expose as much of your skin as possible for 20 to 40 minutes to the midday sun, and do not wash those parts of your skin with soap for the next 24-36 hours. At the start of the winter, you test your blood levels of vitamin D, and depending on the concentration, you supplement accordingly over the course of the dark winter months. Let me emphasise the importance of individual differences in vitamin D needs between people with this example:
My wife and I have the same diet, take the same supplements, and expose our skin in the summer to a comparable extent. However, because we have very different ancestry, different skin types and overall different physiologies, even though most of our blood test results are very similar, her levels of vitamin D are significantly higher than mine, more than twice as high, in fact: hers are 88 ng/ml, which is perfect—well above 50 and well under 100; whereas mine are 40 ng/ml, which is sub-optimal. And this in light of the fact that we have been supplementing with vitamin D during the winter months for a several years now. This means that for this winter, I need to supplement and she does not. It also goes to show that everyone interested in maintaining optimal vitamin D levels needs to monitor and supplement accordingly.
Finally, Vitamin B12 is the last on the list but maybe the most important together with Vitamin D. It is absolutely essential for everything because it is involved in the metabolism of every cell in the human body, and critically important in the function of the brain and entire nervous system. I will have to write about it in a lot more details, but for now, I will just link to an excellent blog by a psychiatrist that works with what she calls Evolutionary Psychiatry. This article is particularly revealing about the vital importance of B12. Since I don’t eat meat and fish very rarely, I always keep a close eye and most of time supplement with B12.
That’s it. I hope this will, on the one hand, encourage you to get these blood tests done, and on the other, give you a better understanding of each one’s biochemical and physiological importance in relation to your health.