Transcript The revelation that fish oil appears useless in preventing heart disease, as I reviewed before, in either heart patients or for those trying to prevent heart disease in the first place, leads one to wonder how this whole fish tale began.
Did CHOs make us human? I doubt it "I like to start with an evolutionary perspective" — Jennie Brand-Miller Today at the Food for Thought ConferenceJennie Brand-Miller argued that dependence on exogenous glucose played a critical role in our evolution.
I and others disagree for several reasons. Synthesising evidence look at the main arguments Brand-Miller put forward in support of exogenous glucose. The brain requires a lot of energy The brain runs on glucose The need for dietary glucose is particularly acute in fetuses The cooking of starch allowed us to get that energy Some modern HGs make significant use of exogenous glucose We have many more copies of amylase than other primates Some of Synthesising evidence have developed persistent lactase We are hard wired to love sweetness Yes, Synthesising evidence brain requires a lot of energy; no it does not have to come from dietary glucose I agree wholeheratedly that our brains require a lot of energy, much more than other organs, and that our needs are many times more acute than in other primates.
Getting this energy was critical for our evolution.
However, the idea that the brain "runs" on glucose, and that this shows a requirement for exogenous glucose is incorrect, and omits well-known evidence. First, our bodies are capable of synthesising enough glucose in the absence of dietary sources to fulfill the most conservative estimates of requirements.
As conceded early in the presentation, we are known to be able survive without exogenous glucose. If we could not supply our brain needs in this way, this would simply not be possible.
That glucose is mostly synthesised out of protein, and the process is called gluconeogenesis. This fact alone is enough to render this argument irrelevant, but there is more.
In the situation for which no dietary glucose is provided, not only can we still make enough glucose endogenously to meet those needs, but in practice what happens is that our needs are different.
Instead of running primarily on glucose, our brains metabolism runs mostly on ketone bodies, and uses glucose for only a small portion of its needs, far less than our capacity to generate it.
Fetal and infant growth does not depend on dietary glucose Brand-Miller also insists that "The fetus grows on the mother's maternal blood glucose. However, she neglects to mention that fetuses make extensive use of ketones. I've covered infant brain growth and the importance of ketone bodies in this context several times, so I won't go into it here.
See Babies thrive under a ketogenic metabolismMeat is best for growing brainsWhat about the sugars in breast milk? In any case, maternal blood glucose is maintained just fine without dietary sources, so even if babies did not use ketones, the point would be moot.
The evolutionary argument Since our brain energy needs are met perfectly well with either a high glucose intake or a low glucose intake, it cannot be reasonable argued that our large brains must have developed under conditions of high glucose intake.
There are still at this point two equally plausible evolutionary hypotheses that would enable the evolutionary development of large brains: An increase in both is also a plausible hypothesis, either together or in alternation.
For simplicity, let's start by considering one state or the other as being the predominant evolved state. Let's review what evolutionary circumstances would be required for each hypothesis, and what other circumstances would support it without being necessary.
Then we can see what evidence we have for those circumstances. Persistent adequate availability of the predominant energy source and essential micronutrients For the exogenous glucose condition to have been the predominant evolved state, we would have required a consistent source of exogenous glucose on a regular basis, year round, for multiple generations.
For the endogenous glucose condition to have been the predominant evolved state, we would have required a consistent source of exogenous fat and protein on a regular basis, for multiple generations.
The reason we would need fat, and not just protein in the gluconeogenesis case, is that we are limited in our ability to metabolise protein.
Protein is better conceived of as a mainly a micronutrient, rather than a macronutrient, because of its structural importance. Besides water, our bodies are primarily made of amino acids and fatty acids.
This is one reason why when we rely on gluconeogenesis for all of our glucose needs, we also have reduced glucose needs.
It spares protein for more important things. Protein availability is also of crucial importance even for the exogenous glucose hypothesis, because it is still a fundamental nutritional need outside of energy requirements. Beyond protein, we would need to supply all of the nutrients that proper brain development requires.
These include the minerals iodine, selenium, iron, zinc, vitamins B12, A, and D, and the vitamin-like choline, and the fatty acids DHA and arachadonic acid. Note that of the minerals listed here, animal sources are much more bioavailable, and that plant sources contain substances that actively interfere with absorption.
Of the vitamins and fatty acids, one B12 is not available even in precursor form, and the others only in precursor form. Humans are known to have low and variable ability to synthesise the necessary components out of precursors.Our Evidence review: An analysis of the evidence for parenting interventions in Australia, is a valuable tool to help policymakers, professionals and agencies make decisions about the suitability of individual parenting programs for achieving particular child and family outcomes..
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The Institute of Health Sciences Education, QMUL, is academic grouping focusing on Medical Education. The evolutionary argument. Since our brain energy needs are met perfectly well with either a high glucose intake or a low glucose intake, it cannot be reasonable argued that our large brains must have developed under conditions of high glucose intake.
There is a growing emphasis on the relationship between the complexity and diversity of the microorganisms that inhabit our gut (human gastrointestinal microbiota) and health/disease, including brain health and disorders of the central nervous system.
His family background? His name got me wondering if he was related to Grady Louis McMurtry whom I had heard of as one of the leaders of the Thelema religion founded by Aleister Crowley. According to his often repeated testimony, Dr Grady S McMurtry was born In San Francisco and raised on the campus of the University of California at Berkeley where his father was a student and then a lecturer.