Addendum: In 2009, I posted the following in my blog. I recently discovered that eCornell has raised its price for the Plant Based Nutrition program to over $1000.00
Original 8/9/09 post
I am considering a career move from teaching in the public school system to something related to diet and nutrition. I recently discovered that eCornell offers a certificate program in plant based nutrition that costs $795.00. The certificate is given by T. Colin Campbell Foundation and eCornell.
Now that my sons are older, I feel I can explore other career paths that I have a passion or an interest for and would find less stressful and more rewarding.
4:40PM - Understanding how the body absorbs food
Carbohydrates
Digestion begins in the mouth by salivary amylase and completed in the small intestine by pancreatic amylase. Monosaccharides, such as glucose, galactose and fructose, are produced by the breakdown of polysaccharides and are transported to the intestinal epithelium by facilitated diffusion or active transport. Facilitated diffusion moves the sugars to the bloodstream.(biology online)
The molar mass of glucose is 180 g mol-1, 120 / 180 = 0.66;
then 0.66 moles glucose hour-1 will be absorbed from the small intestine.(WikiAnswers)
Proteins
Proteins are broken down to peptide fragments by pepsin in the stomach, and by pancreatic trypsin and chemotrypsin in the small intestine. The fragments are then digested to free amino acids by carboxypeptidase from the pancreas and aminopeptidase from the intestinal epithelium. Free amino acids enter the epithelium by secondary active transport and leave it by facilitated diffusion. Small amounts of intact proteins can enter interstitial fluid by endo- and exocytosis.(biology online)
H20 and why it is so Important
Water
The stomach absorbs some water but most is absorbed at small intestine by diffusion.
Regulation of GI Processes
Control mechanisms of the GI system regulate conditions in the lumen of the tract. Reflexes are initiated by:
(1) Distension of wall by volume of luminal contents
(2) Chyme osmolarity
(3) Chyme pH
(4) Chyme concentrations of specific products.
(biology online)
Why I am Lactose Intolerant
Lactose intolerance results from a lack of the enzyme lactase which digests lactose, the sugar in milk. The lack of lactase results in the incomplete digestion of lactose to glucose and galactose.(biology online)
Understanding What Triggers Appetite Control
A hormone, leptin, synthesized by adipose tissue, is released in proportion to the amount of fat in adipose tissue. The hormone acts on the hypothalamus to cause a reduction in food intake by inhibiting the release of a neuropeptide that stimulates eating. It also stimulates metabolic rate and therefore controls changes in energy expenditure. Leptin is important in long-term control.
In short-term, various satiety signals such as insulin, body temperature, presence of food in GI tract act on the hypothalamus to regulate the duration and frequency of meals..
-leptin: "The more fat a person has, the more leptin there is in the bloodstream. In obese people, it seems that the body becomes leptin-resistant -- the signals get jammed. So giving obese people leptin doesn't help them lose weight...It appears that most obese people may be somewhat immunosuppresed"
leptin signaling, via its receptor, occurs in the dopamine neurons in the VTA and that it results in decreased activity of these neurons...Leptin is one of the molecules that signals the brain to modulate food intake. It is produced in fat cells and informs the brain of the metabolic state. If animals are missing leptin, or the leptin receptor, they eat too much and become severely obese." (biology-online.org)
Note: What works in mice does not always work on humans. recent studies show that when leptin levels are reduced in humans, to 80%, there is no change in resting metabolic rate. (Chan JL, 2007)
Basically, more food = more leptin in the bloodstream.
"The bottom line is that while short term fasting typically involves an acute decrease in leptin levels , the consistent increase in Growth Hormone ensures that fat loss remains elevated during periods of fasting. In fact even when Leptin is injected into fasting individuals it doesn’t improve fat burning or decrease GH levels [Chan JL, 2008]...Using short-term flexible intermittent fasting combined with resistance training remains one of the most effective and simple ways to lose weight and reduce your body fat." (Brad Pilon, MS)
-adipose tissue: A connective tissue that contains adipocytes (fat cells). The tissue stores energy in the form of fat within the adipocytes. The tissue is also used for cushioning, thermal insulation of vital organs, lubrication (chiefly in the pericardium), and producing hormones (such as leptin). Obesity in humans depends on the amount of body fat, especially adipose tissue.
There are two types of adipose tissues:
-white adipose tissue (WAT): In humans, the white adipose tissue is about 20% of the body weight in men and 25% of the body weight in women.
-brown adipose tissue (BAT).: The brown adipose tissue is rich in newborns and in hibernating mammals.
-hypothalamus: (Science: anatomy, endocrinology) a portion of the brain which lies beneath the thalamus and secretes substances which control metabolism by exerting an influence on pituitary gland function.
The hypothalamus is also involved in the regulation of body temperature, water balance, blood sugar and fat metabolism. The hypothalamus also regulates other glands such as the ovaries, parathyroids and thyroid. A basal part of the diencephalon governing autonomic nervous system.A section of the brain that is involved in many regulatory functions like osmoregulation and thermoregulation. The hypothalamus has a degree of control over the pituitary gland, and also controls sleeping patterns, eating and drinking and speech. It is also responsible for the secretion of adh (Anti-Diuretic Hormone) via its neurosecretory cells.(biology on-line)
-neuropeptide
-metabolic rate
-energy expenditure
-insulin
-body temperature: The ability to maintain body temperatures within narrow limits is called homeothermy. The total heat content of the body is net difference between heat production and heat loss. In steady state, heat production equals heat loss.
-GI tract
