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Showing posts from September, 2010

High doses of B vitamins slow rate of shrinking brain

Unfortunately, getting older comes with a common consequence affecting up to 16 percent of elderly people – gradual reduction in brain size, which is associated with problems in learning and memory. However, a new study reports that daily supplementation with high doses of B vitamins may help slow the rate of brain degeneration. Oxford researchers gave 168 individuals over the age of 70 supplements containing high doses of folic acid (0.8 milligrams per day), B6 (20 milligrams per day) and B12 (0.5 milligrams per day), or a placebo as part of a randomized, double-blind controlled trial. Then, following two years of the supplementation program, the participants’ brains were assessed using serial volumetric magnetic resonance imaging scans. The researchers reported their results in the September issue of PLoS One: the rate of brain shrinkage, or atrophy, in the group taking the supplements was 53 percent lower in comparison to the group taking the placebo. Their conclusion was that the h

What are the different kinds of seizures

About 2.5 million people in North America have active epilepsy, leaving them susceptible to seizures. However, not all epileptic seizures are the same. They can range in intensity from non-serious to seriously life-threatening. During a seizure, a person may lose a certain degree of consciousness, called impaired consciousness , and may also experience an episode of intense, widespread motor activity called a convulsion . A convulsion can occur without loss of consciousness, but not normally. A seizure happens when the way the brain functions is somehow abnormal causing the impaired consciousness or convulsions. When they happen at the same time, you'd call them a convulsive or sensory seizure. Epilepsy is diagnosed when brain disfunction is disturbed for a relative while or if someone is particularly prone to seizures. You have to have at least two seizures that are not caused by something else, like a disease, before the diagnosis is made. Now, as for the different types: - A par

What are the differences between types of headaches

If there's one thing that will give you a headache, it's trying to remember all of the different kinds of headaches are, and what are their causes or what are they associated with, which can involve simply drinking too much, smoking, stress or fatigue to food poisoning, fever, carbon monoxide poisoning, hypothyroidism, and so on. Basically, any headache is generated pain originating from structures in the head such as the venous sinuses, the tributary veins, the dura at the base of the brain, the arteries within the meninges, or the subarachnoid space. These are all sensitive to stimulation and cause pain. Plus, there are trigeminal, vagus, and upper cervical nerves that can cause pain if under tension, inflamed or compressed. Tension headaches are the most common. They're also very poorly understood and not treated very effectively. They happen just from fatigue, stress, worry. Usually they go away with stress-reduction techniques and relaxation, antidepressants or antianx

Income, obesity, and heart disease in US states

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The figure below combines data on median income by state (bottom-left and top-right), as well as a plot of heart disease death rates against percentage of population with body mass index (BMI) greater than 30 percent. The data are recent, and have been provided by CNN.com and creativeclass.com, respectively. Heart disease deaths and obesity are strongly associated with each other, and both are inversely associated with median income. US states with lower median income tend to have generally higher rates of obesity and heart disease deaths. The reasons are probably many, complex, and closely interconnected. Low income is usually associated with high rates of stress, depression, smoking, alcoholism, and poor nutrition. Compounding the problem, these are normally associated with consumption of cheap, addictive, highly refined foods. Interestingly, this is primarily an urban phenomenon. If you were to use hunter-gatherers as your data sources, you would probably see the opposite relationsh

High doses of B vitamins may slow brain shrinkage and support memory

Unfortunately, getting older comes with a common consequence affecting up to 16 percent of elderly people – gradual reduction in brain size, which is associated with problems in learning and memory. However, a new study reports that daily supplementation with high doses of B vitamins may help slow the rate of brain degeneration. Oxford researchers gave 168 individuals over the age of 70 supplements containing high doses of folic acid (0.8 milligrams per day), B6 (20 milligrams per day) and B12 (0.5 milligrams per day), or a placebo as part of a randomized, double-blind controlled trial. Then, following two years of the supplementation program, the participants’ brains were assessed using serial volumetric magnetic resonance imaging scans. The researchers reported their results in the September issue of PLoS One: the rate of brain shrinkage, or atrophy, in the group taking the supplements was 53 percent lower in comparison to the group taking the placebo. Their conclusion was that the h

Ketones and the Atkins diet

The way the Atkins Diet or any low-carb diet for weight loss works is by limiting the presence of glucose so as to encourage fatty acids to be converted by the liver into ketone bodies. When ketone bodies accumulate in the blood, they lower the pH of the blood. This is a state called ketosis, which is basically when glucose use for energy is slowed down and fatty acid use for energy is sped up. If too many ketone bodies build up, however, then hyperketonemia results and possibly dangerous ketoacidosis. After a good night's sleep, it's known that the fasting state will increase amount of ketone bodies a little, because of depleted glycogen stores. But after 2 days ketone bodies can rise 140-fold. In early starvation, the muscle will use ketone bodies, but then changes to use of fatty acids so that the ketone bodies can be used for the brain. Prolonged starvation causes ketones to become the dominant fuel for the brain, to spare amino acids and loss of muscle. The dramatic rise o

The four reactions of beta-oxidation

Fatty acid oxidation is dependent on entry of fatty acids into the mitochondria, which provides substrate for beta-oxidation in the mitochondrial matrix. The fatty acids are transported in as acylcarnitines. Step 1 in beta-oxidation happens when a fatty acyl CoA that's made at the inner surface of the inner mitochondrial membraine is oxidized by acyl-CoA dehydrogenase. The flavoprotein enzyme uses FAD to accept an electron to complete the reaction. The products end up being trans-enoyl CoA and FADH2, which transfers electrons into the oxidative phosphorylation pathway to recreate FAD. Step 2 in beta-oxidation is hydration of trans-enoyl CoA producing 3-L-hydroxyacyl CoA. Step 3 is when 3-L-hydroxyacyl CoA is oxidized to 3-ketoacyl-CoA intermediate and generates NADH. Step 4 occurs when beta-ketoacyl-CoA thiolase cleaves the 3-ketoacyl-CoA to produce a 2-carbon atom short fatty acyl-CoA and acetylCoA. Acetyl CoA is then ready to enter in the TCA cycle for ATP energy production, and

What are phytates and how do they affect absorption of minerals?

You've heard that spinach has a lot of iron, right? But what you may not know is that spinach is a poor way to get iron because of its content of phytate. Some of the iron in spinach is bound to phytate. Most of the iron you get is absorbed in the small intestine's duodenum. It comes into the mucosal cell as either a free ion or as heme. If iron is attached to phytates, however, its resistant to disassociation in the gut. One way to help improve the absorption is by cooking the spinach to break down ligands attached to the iron. And by combining protein with your spinach, you can cause the stomach to release more hydrochloric acid, lowering the pH and helping free up some more iron. When people have stomach problems that inhibit their ability to release hydrochloric acid (such as when people become older), it's known that a lot of iron is not absorbed at all. In these cases, it may be important to increase the amount of iron in the diet (specifically heme iron from animal f

Low nonexercise activity thermogenesis: Uncooperative genes or comfy furniture?

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The degree of nonexercise activity thermogenesis ( NEAT ) seems to a major factor influencing the amount of fat gained or lost by an individual. It also seems to be strongly influenced by genetics, because NEAT is largely due to involuntary activities like fidgeting. But why should this be? The degree to which different individuals will develop diseases of civilization in response to consumption of refined carbohydrate-rich foods can also be seen as influenced by genetics. After all, there are many people who eat those foods and are thin and healthy, and that appears to be in part a family trait. But whether we consume those products or not is largely within our control. So, it is quite possible that NEAT is influenced by genetics, but the fact that NEAT is low in so many people should be a red flag. In the same way that the fact that so many people who eat refined carbohydrate-rich foods are obese should be a red flag. Moreover, modern isolated hunter-gatherers tend to have low levels

What’s the difference between systemic, essential and secondary hypertension?

Our arteries are origins of potential disease and death. Most of arterial disease happens through sclerosis, or a hardening of the arteries. Previously we called this arteriocleoris, but that’s too general. So now, sclerosis is defined as either medial calcific sclerosis, hypertensive vascular disease or atherosclerosis. Hypertensive vascular disease, in particular, is also called arteriosclerosis because it involves arteriole’s intima and media thickening as a result of cumulative amounts of plasma proteins,plus overproduction of basement membrane and extracellular matrix. Systemic hypertension, or high blood pressure, is associated with hypertensive vascular disease and is a problem that is widespread. The term systemic distinguishes the condition from a local high blood pressure as in pulmonary (lung) or portal hypertension (hepatic portal system). The chief risk factors are genetics, race, older age, smoking, obesity and stress. Essential hypertension does not usually have an ident

Thrombosis and thromboembolism

When there’s a problem in normal blood flow, we call it a hemodynamic disorder. They are caused when there’s an overcoagulation of blood forming a thrombus in side a vessel. The process is called thrombosis, which can also result in embolism or infarction. When a thrombus forms, it’s made up of platelets, erythrocytes, leukocytes and fibrin. It doesn’t form outside a blood vessel as clots do, but instead forms at a blood vessel wall. The thrombosis begins at a point attached to the vascular wall where platelets group together. A coagulation cascade is triggered, but there’s no threatened blood loss. How does this happen? Endothelial damage, altered blood flow, or a state of blood hyper coagulation. Endothelial damage can result from hemodynamic stress as blood flow under pressure causes arteries to expand and elongate. The pressure can be produced due to hypertension, a major cause. But a second major cause is atherosclerosis. Abnormal blood flow can cause more platelet contact with en

Blood: Circulating Life

Blood is a fluid that is made up of plasma and elements, which includes erythrocytes, leukocytes and platelets. At times the plasma volume and concentration can be affected as in fluid and electrolyte imbalances, but other times blood coagulation can have its disorders. When elements are produced in the blood, we call this hemopoiesis. Hemopoiesis takes place through mitosis and differentiation of daughter cells. The cells specialize to produce a specific function. Most of the hemopoiesis happens in red bone marrow (about 2 liters of red marrow is in an adult’s skeleton). Formed element has very little reproductive abilities. Stem cells are able to differentiate into all hemopoietic cells, or even form new stem cells. Progenitor cells are derived from stem cells but can’t self-renew themselves, so are said to be commited to a cell line. Erythropoises, red blood cell formation, happens through mitosis. Then hemoglobin synthesis happens, followed by loss of organelles. The reticulocyte i

Growth of Tumors

When an overgrowth of tissue forms into neoplastic mass, it’s called a neoplasm or tumor. Neoplasia can have a deadly outcome such as in cancer. It is the No. 2 killer in North America with 30 percent suffering from the disease. A quarter of North American adults die of cancer. It also kills more children than any other disease. Oncology is the study of tumors and when we talk about tumors, there’s two important characteristics – pattern of growth and tissue of origin. A tumor is benign if growth is slow, orderly and the tumor is localized. It’s malignant if the growth is rapid, disorderly and invades other normal tissues. Cancer is result of a malignant tumor that spreads to distant points in the body. We add the suffix “-oma” when designating a benign tumor and what in which tissue it originates. An osteoma is a benign tumor in bone. A fibroma is a benign tumor in fibrous tissue. If a malignant tumor arises, then it is named depending on which embryonic tissue it originates from. If

Green tea could lead to longer life by protecting DNA

Last year, scientists from The Chinese University of Hong Kong found a positive association between high consumption of tea (Camellia sinensis) and longer telomere length – a marker of younger “biological age” – and living an average of five years longer, but it was unclear just how much of an impact was made by the tea. Now scientists from Hong Kong Polytechnic University have discovered, through a cell culture study then followed by a controlled trial of supplementation in humans, that drinking two cups of green tea daily may offer notable DNA protection from oxidation. Writing in the September issue of British Journal of Nutrition, the study’s authors state that the “genoprotective effects of green tea lend support to its use as a functional food and provide scientific evidence for the more confident recommendation of regular intake of green tea for health promotion.” In the in vitro trial, the scientists prepared an infusion of tea that was used to treat human immune cells. The cel

Strong causation can exist without any correlation: The strange case of the chain smokers, and a note about diet

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Researchers like to study samples of data and look for associations between variables. Often those associations are represented in the form of correlation coefficients, which go from -1 to 1. Another popular measure of association is the path coefficient, which usually has a narrower range of variation. What many researchers seem to forget is that the associations they find depend heavily on the sample they are looking at, and on the ranges of variation of the variables being analyzed. A forgotten warning: Causation without correlation Often those who conduct multivariate statistical analyses on data are unaware of certain limitations. Many times this is due to lack of familiarity with statistical tests. One warning we do see a lot though is: Correlation does not imply causation. This is, of course, absolutely true. If you take my weight from 1 to 20 years of age, and the price of gasoline in the US during that period, you will find that they are highly correlated. But common sense tel

How the healing process really happens

Healing is a pretty fascinating process that our body is capable of producing all on its own in response to destroyed tissue. The process replaces lost tissue and restores structure, strength and function. It’s intertwined with inflammation and so there’s overlap between the responses as you’ll note after reading these posts and previous ones. It all happens when tissue that is undamaged next to the damaged tissue begins to proliferate. Functional cells called parenchyma combine to form a stroma. Then, there’s two different ways healing takes place: regeneration or repair. Regeneration is when tissue is replaced. Repair is when fibrous car tissue is used to fill gaps. Basically, reestablishing epithelium at damaged spots come with four components: - Regeneration: This is when cells lost are replaced by mitosis by adjacent parenchymal cells. It’s ideal because new tissue is ideal for normal function. - Repair: This is when fibrous connective tissue, or a scar (made of strong collagen) i

How cell injury happens and what is the result?

A normal cell has a general organization at a chemical level that involves atoms, molecules moving around in complex fashion that ultimately is critical to the way we live. The cell membrane and various organelles such as the mitochondria all have vital roles to play. At the cellular level, injury is a result of three basic causes: deficiency, intoxication, or trauma. A deficiency is when the cell lacks a compound of a sort that causes interference with function such as when there’s a dietary deficiency of B vitamins. Intoxication is when a compound present actually poisons the cell, interfering with function such as when a biological infection, or toxic product in the cell like barbiturates. Trauma is when there is actual physical injury to the cell, causing loss of cell integrity such as hypothermia causing ice crystals or hyperthermia causing denaturation of cellular proteins. The cell can respond in various ways by adapting with reversible (functional or structural) and, sometimes,

The basics of health and disease

What does healthy mean? Some would call it the absence of disease, or when a person can fully use all of his or her physical or mental capacities. But when what we understand as the concept of health is disrupted, in some way or another (which happens inevitably), we call it disease. The study of the cause of this disease is what we call etiology and the field of etiological study can be specific, as in viral etiology or genetic etiology. Or, when the etiology of a disease is unknown, then idiopathic. Unlike genetic etiology (think cystic fibrosis), which comes with a genetic structural or functional defect, congenital etiology has to do with factors affecting an embryo’s development in utero (think fetal alcohol syndrome). The largest category of etiology is acquired disease. These are diseases that develop despite normal genes and embryonic development. Think everything else from tuberculosis to flu, to heart disease and cancer. Diseases come with symptoms, signs or both. Signs are w

What is inflammation?

Inflammation is a normal response of the body that involves an increase of blood flow to a site of injury. The signs of inflammation are redness (rubor), heat (calor), swelling (tumor) and pain (dolor). One other classic sign is loss of function (function laesa). Acute inflammation is a dramatic localized response to injury. It comes vascular changes increasing blood flow (hyperemia) to the area that cause the redness and warmth as observed along with swelling. There’s also a cellular component, in which large numbers of white blood cells move to the injury to stop infectious agents and clear debris. The cells that come form what is referred to as an exudates. Chronic inflammation is when inflammation lasts beyond six weeks (subacute applies to inflammation beyond a week, but not lasting as long as six weeks). A chronic response can last months and years. It is essentially a “standoff” between an injury and the body’s defense. They resist each other, but neither is strong enough to bea

The China Study II: Wheat flour, rice, and cardiovascular disease

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In my  last post  on the China Study II, I analyzed the effect of total and HDL cholesterol on mortality from all cardiovascular diseases. The main conclusion was that total and HDL cholesterol were protective. Total and HDL cholesterol usually increase with intake of animal foods, and particularly of animal fat. The lowest mortality from all cardiovascular diseases was in the highest total cholesterol range, 172.5 to 180; and the highest mortality in the lowest total cholesterol range, 120 to 127.5. The difference was quite large; the mortality in the lowest range was approximately 3.3 times higher than in the highest. This post focuses on the intake of two main plant foods, namely wheat flour and rice intake, and their relationships with mortality from all cardiovascular diseases. After many exploratory multivariate analyses, wheat flour and rice emerged as the plant foods with the strongest associations with mortality from all cardiovascular diseases. Moreover, wheat flour and rice

What causes a fever?

When inflammation comes with a body temperature that is elevated above normal, we call it a fever or pyrexia. The change in temperature is not a defect, but an adjustment by the hypothalamus to a new set point. The set point is established in consequence of release of fever-producing factors called pyrogens, whether endogenous or exogenous. Endogenous pyrogens are produced upon stimulation of exogenous agents. The fever is a response to infectious, toxic or immunologic disease or injury, at least in warm-blooded animals – although cold-blooded animals like lizards often treat themselves similarly by lying in the sun to raise body temperature. The fever enhances functions of the immune system and phagocytosis. Also, there are a few bacteria and viruses that reproduce more slowly in the heated temperature because of possible interference with uptake of iron. So, our initial idea of a fever as something to treat may actually be our bodies’ ways of treating themselves to some kind of moder

Giving Children the Chance at a Healthy Future

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Encouraging healthy habits like exercise and eating right early on helps stave off childhood obesity. September is the first-ever officially proclaimed National Childhood Obesity Awareness Month in the United States. It’s a dedicated time for recognizing the seriousness of obesity on health and building awareness about the rise in obesity rates and its impact on our youth. The government statistics about childhood obesity are shocking: - Childhood obesity has increased more than fourfold among ages 6 to 11 in the United States - More than 23 million children and teenagers in the United States ages 2 to 19 are obesity or overweight - Nearly one third of America’s children are at early risk for Type 2 diabetes, high blood pressure, heart disease and even stroke - The current generation may have shorter lifespans than their parents During this month of national attention on this epidemic, parents and responsible adult role models can surely do their part by encouraging the overall goal o

The China Study II: Cholesterol seems to protect against cardiovascular disease

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First of all, many thanks are due to Dr. Campbell and his collaborators for collecting and compiling the data used in this analysis. This data is from this site , created by those researchers to disseminate the data from a study often referred to as the “China Study II”. It has already been analyzed by other bloggers. Notable analyses have been conducted by Ricardo at Canibais e Reis , Stan at Heretic , and Denise at Raw Food SOS . The analyses in this post differ from those other analyses in various aspects. One of them is that data for males and females were used separately for each county, instead of the totals per county. Only two data points per county were used (for males and females). This increased the sample size of the dataset without artificially reducing variance (for more details, see “Notes” at the end of the post), which is desirable since the dataset is relatively small. This also allowed for the test of commonsense assumptions (e.g., the protective effects of being fem