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Basal Metabolic Rate as a biomarker for Calorie Restriction

In his book, Beyond the 120 Year Diet: How to Double Your Vital Years-, Dr. Walford describes Calorie Restriction as a method for extending maximum life span.[1] Chapter 2 describes functional tests for estimating the rate of aging. He calls these the "biomarkers of aging" and divides them into categories for determining functional age, predictive value for remaining life expectancy, and disease susceptibility or segmental aging (p. 32).

Dr. Walford also mentions "biomarkers of success" which determine whether a person is successfully following a CRON diet. He says, "Are you really doing what it takes to retard aging or are you just playing around? You don't have to wait six years to find the answer to this important question. Six months is time enough. Your doctor can do a number of tests before you start and then six months later, tests which show rapid changes if you are on track with the program, tests including levels of blood sugar, cholesterol, blood pressure, and a number of other parameters."

With regard to metabolism, Dr. Walford describes a study of 54 farmers (p. 64) that revealed "metabolic efficiency, expressed as work done in relation to energy intake, was actually 80 percent higher for the ten farmers with the lowest intake (1,535 calories) than for those with the highest intake (2,382 calories). Heights and weights did not differ and the two groups performed the same amount of labor." Dr. Walford goes on to say: "A major secret of health and longevity is to be always below your set point, maintaining yourself on a high enough quality diet that you are not deficient in any essentials, and to operate at maximum metabolic efficiency. This is, in fact, the central idea of my longevity program."

In describing his experience in the Biosphere[2], Dr. Walford describes that Keys showed in the Minnesota experiment that 6 mo of severe energy restriction reduced the resting metabolic rate (RMR) in absolute terms by 39% or by 16% when expressed per kilogram of metabolically active tissue. A more recent study showed that a 40% CR diet for 21 days reduced BMR by 12%.[3] Studies of anorexic patients, who are consistently calorically restricted, also demonstrate that their BMR is significantly lower than that of control subjects. One study found the BMR of anorexic patients to be lower by 20.8%, or by 11.5% after adjustment for fat-free mass.[4]

BMR seems like a good biomarker for Calorie Restriction because it decreases within a few days of the onset of CR, and because it remains lower as long as CR is continued. The absolute value of the BMR in kJ/min may be a useful biomarker for determining whether you are "really doing what it takes to retard aging".

Learn more about Calorie Restriction

[1] Roy Walford, M.D., "Beyond the 120 Year Diet: How to Double Your Vital Years", 2000.

[2] Christian Weyer, Roy L Walford, Inge T Harper, Mike Milner, Taber MacCallum, P Antonio Tataranni and Eric Ravussin, "Energy metabolism after 2 y of energy restriction: the Biosphere 2 experiment", American Journal of Clinical Nutrition, Vol. 72, No. 4, 946-953, October 2000.

[3] Friedlander AL, et al. "Three weeks of caloric restriction alters protein metabolism in normal-weight, young men" Am J Physiol Endocrinol Metab., 2005 Sep;289(3):E446-55. Epub 2005 May 3. PMID: 15870104

Nine young, normal-weight men [23 +/- 5 y, 78.6 +/- 5.7 kg, peak oxygen consumption (Vo2 peak) 45.2 +/- 7.3 ml.kg(-1).min(-1), mean +/- SD] were underfed by 40% of the calories required to maintain body weight for 21 days and lost 3.8 +/- 0.3 kg body wt and 2.0 +/- 0.4 kg lean mass. Protein intake was kept at 1.2 g.kg(-1).day(-1). BMR declined from 1,898 +/- 262 to 1,670 +/- 203 kcal/day.

[4] Polito A, Fabbri A, Ferro-Luzzi A, Cuzzolaro M, Censi L, Ciarapica D, Fabbrini E, Giannini D. Basal metabolic rate in anorexia nervosa: relation to body composition and leptin concentrations. Am J Clin Nutr. 2000 Jun;71(6):1495-502. PMID: 10837290
The BMR of AN patients (2.73 ± 0.37 kJ/min) was significantly lower than that of control subjects (3.45 ± 0.34 kJ/min) (P < 0.001), even after adjustment for FFM (2.92 ± 0.33 kJ/min in AN patients and 3.30 ± 0.26 kJ/min in control subjects; P < 0.004).

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2007-07-18 

Can a soulmate make you happy?

Beating Hearts

Actually, that is a trick question. Your happiness should come from within yourself. Nobody can make you happy, just like nobody else can sleep for you. Certainly, it is easier to be happy with someone who meets your expectations and complements your personality rather than with someone who opposes you and makes it more difficult to achieve your goals.

We often think that a soulmate is someone who shares the same interests and is exactly like ourselves. This is not always the case. Some personality traits work better when the partner has balancing traits that result in a win-win relationship for both persons. Two dynamic individuals may be frustrated when both want different things. A dynamic individual and a passive individual may find happiness if they can adjust to the different pace of their partner.

The most important feature of a good relationship is honesty. Many relationships end when trust is broken or secrets are discovered. Financial problems or difficulties with relatives can also stress a relationship and end it. People often approach a relationship with great optimism, only to be disillusioned later. The problem of failed relationships is usually due to making decisions based on emotions rather than on impartial evaluation of the compatibility of the personalities.
Try the Personality Compatibility Analysis

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2007-07-16 

The origin of sex

Somerset Island

The arctic Canadian island of Somerset, located close to the Qikiqtaaluk Region of Nunavut, has some rocks containing fossils of red algae deposited approximately 1200 million years ago during the Mesoproterozoic Era. Because the fossils are very well preserved, it has been possible to identify the algae as Bangiomorpha pubescens and to study the cell-division patterns of the multicellular filaments in the geologic record.

The spore/gamete formation shows that the algae had been sexually reproducing, and this is the oldest reported occurrence in fossils.[1] Eukaryotes, which are organisms whose cells contain a distinct membrane-bound nucleus, appeared around 1600 million years ago and became successful because sex provided the advantages of genetic recombination and it allowed complex multicellularity. The first appearance of sexual reproduction is associated with the first stratigraphic occurrence of complex multiple-cell organisms. Eukaryotic multicellularity is the innovation that established organism morphology as a significant factor in biological evolution.
See the Geologic and Biological Timeline of the Earth

[1] Nicholas J. Butterfield, Bangiomorpha pubescens n. gen., n. sp.: implications for the evolution of sex, multicellularity, and the Mesoproterozoic/Neoproterozoic radiation of eukaryotes, Paleobiology; September 2000; v. 26; no. 3; p. 386-404.

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2007-07-15 

The silent E in English

In Spanish, the written language is a fairly accurate phonetic representation of the words. This is why "baseball" is spelled "beisbol". In English, the spelling of words is more the result of tradition, rather than phonetics. Every person who has ever tried to write English knows that the spelling of English words has to be memorized. The English language resulted from a mishmash of Germanic and Anglo-Saxon heritage modified by the influence of the Roman and Norman conquests.

What is the function of the silent "E"? The silent "E" is responsible for the difference between the pronunciation of "HAT" and "HATE" or between "CAP" and "CAPE" or between "HOP" and "HOPE". Although the final "E" is not pronounced, it indicates how the vowel preceding the consonant should be pronounced. The "A" in "HAT" is called a short vowel, whereas the "A" in "HATE" is called a long vowel. Long vowels are usually diphthongs, i.e., two adjacent vowels with a smooth transition from one vowel to another.

Learn how short and long vowels affect the patterns of conjugation of regular verbs in English.

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2007-07-12 

What is dietary fiber?

Vegetables, fruits, and cereals contain sugars, starches, and complex carbohydrates. Sugars and starches are easily digested. Saliva contains amylase, an enzyme that breaks down starches into digestible sugars. Complex carbohydrates may consist of resistant starch, as well as soluble and insoluble fiber. Resistant starch is not easily broken down into its component sugars, and thus, has a lower Glycemic Index, which is the rate at which the sugar from carbohydrates is released into the body. Complex carbohydrates are found in whole grains.

Soluble and insoluble fiber are completely indigestible and pass through the body basically unchanged, except that soluble fiber can be fermented by microorganisms in the large intestine. These colonic bacteria produce vitamins and short-chain fatty acids that are absorbed by the intestine and have beneficial effects. Soluble fiber also binds bile acids produced by the liver to aid digestion and prevents the bile acids from being re-absorbed, thus lowering cholesterol. Oatmeal and oat cereals reduce cholesterol by this mechanism.
Learn more about sugars, starches, and complex carbohydrates

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2007-07-07 

You lose weight through your lungs

Lungs

Everybody knows that weight is gained through the mouth. Your weight will increase in proportion to the amount of food ingested. The more food that you eat, the more weight that you will gain. After the food is digested in the stomach, nutrients are absorbed by the intestines. The nutrients get stored as glycogen, muscle, or fat. Glycogen is a complex sugar similar to starch which can be converted to glucose when needed. The body does not have a high capacity for storing glycogen, so any excess nutrients get converted to fat and stored as adipose tissue.

Indigestible fiber and other waste products from the food are excreted as feces. The nitrogen compounds in proteins and nucleic acids get metabolized into urea and uric acid which are discharged in the urine. Fats and carbohydrates get metabolized into carbon dioxide which is expelled through the lungs. This is why it is so hard to lose weight -- as incredible as it may seem, the only way to lose the fat from a pot belly is through the nose, one breath at a time.

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2007-07-03 

Are you getting parasites from your pets?

Dog licking

Pets can be a such good friends. It is so uplifting to be greeted by a dog wagging its tail or by a cat rubbing its body along your legs. Pets can be great companions, but it is necessary to take care of their health to make sure that you too stay healthy.

Infections that can be passed from animals to humans are called zoonotic diseases, or zoonoses. Roundworms, hookworms, and Toxoplasma are parasitic infections that can be transmitted from your pets to you or other family members. The larval stages of hookworms, for example, can live in moist soil that has been contaminated by feces of infected animals. If your dog walks in one of these areas, it may become infected, and eventually, you too may become infected. Roundworms pose a more direct problem because their life cycle causes the larvae to be coughed from the lungs and then swallowed to reside in the intestines. Getting licked by a dog during this stage may transmit the parasites to you directly.

Owning a pet is a rewarding experience, but it also gives you the responsibility of disposing of their waste properly and of visiting a veterinarian regularly to make sure that your pets do not endanger your family's health.
Learn about Hygiene, Viruses, Bacteria, and Parasites

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2007-07-01 

Aspirin can give you ulcers

Aspirin can give you ulcers

Many people take aspirin to relieve arthritis pain or to prevent heart attacks. The American Heart Association recommends aspirin use for patients who have had heart attacks or strokes caused by blood clots. Unfortunately, aspirin and other non-steroidal anti-inflammatory drugs (NSAIDs) can cause ulcers or gastrointestinal bleeding that may result in death or require hospitalization. Various studies have shown an association between increased prescription of COX2 inhibitors and a 10% increase in hospitalization rates for upper gastrointestinal bleeding. In the UK it has been estimated that more than 40% of ulcer bleeding and deaths from ulcers are related to NSAID use.

Helicobacter pylori, a bacterium that can infect the digestive tract, increases the risk of ulcer complications in NSAID users almost twofold. Patients with a history of ulcers should be tested for H. pylori, and any infection should be eradicated before starting NSAID therapy.

If you take aspirin regularly and you have a burning feeling or pain in your stomach, or if you see blood in your stool, you should seek medical advice promptly. If the bleeding is severe, you may faint and you may not be able to call for help.

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2007-06-28 

Are you losing your memory? It could be your diet!

Brain Anatomy

Did you know that the brain is about 60% fat? It makes sense that if you eat the wrong fats, your brain is going to suffer. You are what you eat. Ann-Charlotte Granholm of the Medical University of South Carolina in Charleston presented the results of a study which showed that trans-fats adversely affected rats' learning ability, at a meeting of the Society for Neuroscience.[1]

Granholm compared rats on a high-fat diet of about 12% soybean oil with those on a high trans-fat diet, containing 10% hydrogenated fat and 2% cholesterol. Rats on the high trans-fat diet showed learning difficulties when the animals were required to remember the position of hidden platforms in a water-filled maze. The animals on the trans-fat diet learned more slowly and made more errors, particularly as the task was made harder. They were about five times worse at the task, she says, than the animals on the soybean oil diet.

The brains of the animals fed trans fats also showed signs of damage and inflammation in a region called the hippocampus, which is important for learning and memory. The hippocampus is located inside the temporal lobe of the brain.

Trans fats have been shown to double the risk of cardiovascular disease. Now, they are also associated with decreased mental performance. Do you think that the increasing rates of Attention Deficit Disorder (ADD) and autism in our society are just a coincidence? Fetuses are exposed to trans fats during pregnancy, and as soon as the babies are born, they start eating trans fats because the trans fats from our foods end up even in the mother's milk.[2]

What can you do about it? Read the labels! Avoid all foods with hydrogenated fats and partially hydrogenated fats.
Learn to read labels

[1] NewScientist.com news service
[2] Ratnayake WM, Chen ZY, Trans, n-3, and n-6 fatty acids in Canadian human milk. Lipids, 1996 March; 31 Suppl:S279-82. PMID: 8729134

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2007-06-24 

Summer Grilling: Don't eat burned meat

Grilling Hamburgers

If you have ever eaten a piece of meat that was overcooked on the grill, you have tasted the bitterness of the burned corners of the meat. Eating the blackened crust of meat cooked at very high temperatures can increase your risk of developing colorectal, pancreatic, and breast cancers. That is what your taste buds were trying to tell you.

Cooking meats such as beef, pork, chicken, and fish at high temperatures creates heterocyclic amines (HCAs) that are carcinogenic.[1] Cooking at high temperatures also produces advanced glycation endproducts (AGEs) that increase inflammation and contribute to vascular and renal complications of people with diabetes.[2] One study conducted by researchers from the National Cancer Institute (NCI) found a link between individuals with stomach cancer and the consumption of cooked meats. After examining the diets and cooking habits of 176 people diagnosed with stomach cancer and 503 people without cancer, the researchers found that those who ate their beef medium-well or well-done had more than three times the risk of stomach cancer than those who ate their beef rare or medium-rare. Other studies have shown that high intakes of well-done, fried, or barbecued meats are associated with an increased risk of developing colorectal, pancreatic, and breast cancer.

Frying, broiling, and barbecuing produce the largest amounts of HCAs because the meats are cooked at very high temperatures. One study showed a threefold increase in the content of HCAs when the cooking temperature was increased from 200°C to 250°C (392°F to 482°F). Oven roasting and baking are done at lower temperatures, so lower levels of HCAs are formed, but gravy or glazes made from meat drippings contain substantial amounts of HCAs. Stewing, boiling, or poaching are done at or below 100°C (212°F); cooking at this low temperature creates negligible amounts of the harmful chemicals.

To reduce burning the meat, encase it in foil, or cook it at a lower temperature.

[1] Heterocyclic Amines in Cooked Meats

[2] Negrean M, et al, Effects of low- and high-advanced glycation endproduct meals on macro- and microvascular endothelial function and oxidative stress in patients with type 2 diabetes mellitus. Am J Clin Nutr. 2007 May;85(5):1236-43.
PMID: 17490958

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