Wednesday, September 15, 2010

Dandruff



Seborrhea (Dandruff)

It is a common form of skin eczema that occurs in parts of the body with high oil (sebum) production. Body areas that are commonly affected include the scalp, ears, face, chest, and folds of skin, such as the underarms or the skin below breasts or overhanging abdominal folds. The cause of seborrhea is unknown, although a yeast that often lives on the skin, Malassezia furfur, may play a role.
One common manifestation of seborrhea that affects the scalp is dandruff. Scalp seborrhea can also present as thick, flaky, localized patches of scale. On the face, seborrhea produces reddish-brown, dry-looking, or thick, greasy scales on the eyebrows, sides of the nose, and behind the ears. Reddish, scaly patches may also appear in the folds of skin mentioned above. Although skin affected by seborrhea may feel "dry," moisturizing only makes them redder.
Scalp seborrhea and dandruff do not cause permanent hair loss. Often, scalp seborrhea doesn't even itch significantly. Seborrhea can appear during infancy, starting shortly after birth and lasting several months. It may affect the scalp ("cradle cap") or produce scaly patches on the body. Adults of all ages may develop seborrhea, too, especially on the scalp and face.
Some people who have weakened immune systems, such as those on chemotherapy  or  with HIV disease or certain neurological disorders, may have very severe seborrhea. It is important to emphasize, however, that seborrhea is a very common condition, affecting perhaps 5% of the population (with men predominating). The vast majority of those who have it are completely healthy and have no internal or immune problems.

Causes:

As the epidermal layer continually replaces itself, cells are pushed outward where they eventually die and flake off. In most people, these flakes of skin are too small to be visible. However, certain conditions cause cell turnover to be unusually rapid, especially in the scalp. For people with dandruff, skin cells may mature and be shed in 2–7 days, as opposed to around a month in people without dandruff. The result is that dead skin cells are shed in large, oily clumps, which appear as white or grayish patches on the scalp, skin and clothes.
Dandruff has been shown to be the result of three required factors


  1. Skin oil commonly referred to as sebum or sebaceous secretions
  2. The metabolic by-products of skin micro-organisms (most specifically Malassezia yeasts)
  3. Individual susceptibility
Common older literature cites the fungus Malassezia furfur (previously known as Pityrosporum ovale) as the cause of dandruff. While this fungus is found naturally on the skin surface of both healthy people and those with dandruff, it was later discovered that a scalp specific fungus, Malassezia globosa, is the responsible agent. This fungus metabolizes triglycerides present in sebum by the expression of lipase, resulting in a lipid byproduct oleic acid (OA). Penetration by OA of the top layer of the epidermis, the stratum corneum, results in an inflammatory response in susceptible persons which disturbs homeostasis and results in erratic cleavage of stratum corneum cells.
Rarely, dandruff can be a manifestation of an allergic reaction to chemicals in hair gels, sprays, and shampoos, hair oils, or sometimes even dandruff medications like ketoconazole.
There is some evidence that excessive perspiration and climate have significant roles in the pathogenesis of dandruff.

Home Remedies:

Dandruff treatment using Fenugreek Seeds

The use of fenugreek seeds is one of the most important remedies in the treatment of dandruff. Two tablespoons of these seeds should be soaked overnight in water and ground into a fine paste in the morning. This paste should be applied all over the scalp and left for half an hour. The hair should then be washed thoroughly with soap-nut (ritha) solution or acacia concinna.

Dandruff treatment using Lime

The use of a teaspoon of fresh lime juice for the last rinse, while washing the hair, is another useful remedy. This not only leaves the hair glowing but also removes stickiness and prevents dandruff.

Dandruff treatment using Green Gram Powder

A valuable prescription for removal of dandruff is the use of green gram powder. The hair should be washed twice a week with two tablespoons of this powder mixed with half a cup of curd.

Dandruff treatment using Beet

Beets have been found useful in dandruff. Both tops and roots should be boiled in water and this water should be massaged into the scalp with the finger tips every night. White beet is better for this purpose.

Dandruff treatment using Snake Gourd

The juice of snake gourd has been found beneficial in the prevention and treatment of dandruff. The juice should be rubbed over the scalp for this purpose.

Dandruff treatment using Other Remedies

Dandruff can be removed by massaging the hair for half an hour with curd which has been kept in the open for three days, or with a few drops of lime juice mixed with indian gooseberry juice every night, before going to bed. Another measure which helps to counteract dandruff is to dilute cider vinegar with an equal quantity of water and dab this on to the hair with cotton wool inbetween shampooing. Cider vinegar added to the final rinsing water after shampooing also helps to disperse dandruff.
OTHER TREATMENTS:
Hot oil therapy is the best method to cure dandruff. Massage hot oil into the scalp at bedtime. Next morning an hour before the bath, rub lemon juice mixed with cosmetic vinegar into the scalp with cotton wool.

Mix beetroot juice in vinegar and apply on the scalp. Ginger juice and beetroot juice mixed together and applied on the scalp are also beneficial.

During the first five days of the treatment when the patient takes an all-fruit diet, a warm-water enema should be taken daily to cleanse the bowels. Simultaneously, an attempt should be made to keep the body in good health.

Mild dandruff is the result of excessive oiliness of the skin and not due to dryness of the scalp. Chronic dandruff may occur due to psoriasis of the scalp.

People should avoid spicy and greasy food because it helps dandruff to increase and spread. People should add more vegetables and fruits on the diet. It is very essential to take fresh foods avoid taking tinned and canned foods add more green vegetables and fruits.

Egg shampoo is one of the oldest beauty recipes. Eggs are full of protein. Simply wash your hair with egg. Beat up one or two eggs with a cup of water and thoroughly massage this into your wet hair for about five to ten minutes. Rinse off thoroughly and remember not to use hot water. There is another method to use egg shampoo. Simply beat one egg in a cup of water and mix to it 1 to 2 tablespoons shampoo. Do not worry about which shampoo has to be used. As a last rinse use the juice of one lemon in a cup of hot water. Continue this complete treatment once a week for three months, then once a fortnight for the next two months.


Thursday, September 9, 2010

Pigment Diseases



1- Addison's Disease

Addison’s disease (also chronic adrenal insufficiency, hypocortisolism, and hypocorticism) is a rare endocrine disorder wherein the adrenal glands produce insufficient steroid hormones (glucocorticoids and often mineralocorticoids). It is generally diagnosed via blood tests and medical imaging. Treatment involves replacing the absent hormones (oral hydrocortisone and fludrocortisone). Regular follow-up treatment and monitoring for other health problems is necessary. Addison’s disease is named after Dr. Thomas Addison.

Symptoms

The symptoms of Addison's disease develop insidiously, and it may take some time to be recognized. The most common symptoms are fatigue, lightheadedness upon standing or while upright, muscle weakness, fever, weight loss, difficulty in standing up, anxiety, nausea, vomiting, diarrhea, headache, sweating, changes in mood and personality, and joint and muscle pains. Some have marked cravings for salt or salty foods due to the urinary losses of sodium. Affected individuals may note increased tanning since adrenal insufficiency is manifested in the skin primarily by hyperpigmentation. Untreated, an Addisonian crisis can be fatal. It is a medical emergency, usually requiring hospitalization. Characteristic symptoms are:

Sudden penetrating pain in the legs, lower back or abdomen

Severe vomiting and diarrhea, resulting in dehydration

Low blood pressure

Syncope (loss of consciousness)

Hypoglycemia

Confusion, psychosis, slurred speech

Severe lethargy

Hyperkalemia

Hypercalcaemia

Convulsions

Fever

Causes:

Causes of adrenal insufficiency can be grouped by the way they cause the adrenals to produce insufficient cortisol. These are adrenal dysgenesis (the gland has not formed adequately during development), impaired steroidogenesis (the gland is present but is biochemically unable to produce cortisol) or adrenal destruction (disease processes leading to the gland being damaged).

2- Drug-induced pigmentation: Amiodarone

Long-term administration of amiodarone is associated with a blue-grey discoloration of the skin. This is more commonly seen in individuals with lighter skin tones. The discoloration may revert upon cessation of the drug. However, the skin color may not return completely to normal. Individuals taking amiodarone may become more sensitive to the harmful effects of UV-A light. Using sunblock that also blocks UV-A rays appears to prevent this side effect.

3- Melasma

Melasma (also known as "Chloasma faciei" or the mask of pregnancy when present in pregnant women) is a tan or dark skin discoloration. Although it can affect anyone, melasma is particularly common in women, especially pregnant women and those who are taking oral or patch contraceptives or hormone replacement therapy (HRT) medications. It is also prevalent in men and women of Native American descent (on the forearms) and in men and

women of German/Russian and

desc

descent

(on the face)

.

Symptoms

The symptoms of melasma are dark, irregular patches commonly found on the upper cheek, nose, lips, upper lip, and forehead. These patches often develop gradually over time. Melasma does not cause any other symptoms beyond the cosmetic discoloration.

Causes

Melasma is thought to be the stimulation of melanocytes or pigment-producing cells by the female sex hormones estrogen and progesterone to produce more melanin pigments when the skin is exposed to sun. Women with a light brown skin type who are living in regions with intense sun exposure are particularly susceptible to developing this condition.

Genetic predisposition is also a major factor in determining whether someone will develop melasma.

The incidence of melasma also increases in patients with thyroid disease. It is thought that the overproduction of melanocyte-stimulating hormone (MSH) brought on by stress can cause outbreaks of this condition. Other rare causes of melasma include allergic reaction to medications and cosmetics.

Melasma Suprarenale (Latin - above the adrenals) is a symptom of Addison's disease, particularly when caused by pressure or minor injury to the skin, as discovered by Dr. FJJ Schmidt of Rotterdam in 1859.

Diagnosis

Melasma is usually diagnosed visually or with assistance of a Wood's lamp (340 - 400 nm wavelength). Under Wood's lamp, excess melanin in the epidermis can be distinguished from that of the dermis.

Treatment

The discoloration usually disappears spontaneously over a period of several months after giving birth or stopping the oral contraceptives or hormone replacement therapy.

Treatments to hasten the fading of the discolored patches include:

Topical depigmenting agents, such as hydroquinone (HQ) either in over-the-counter (2%) or prescription (4%) strength. HQ is a chemical that inhibits tyrosinase, an enzyme involved in the production of melanin.

Tretinoin, an acid that increases skin cell (keratinocyte) turnover. This treatment cannot be used during pregnancy.

Azelaic acid (20%), thought to decrease the activity of melanocytes.

Facial peel with alpha hydroxyacids or chemical peels with glycolic acid.

Laser treatment. A Wood's lamp test should be used to determine whether the melasma is epidermal or dermal. If the melasma is dermal, Fraxel laser has been shown in studies to provide improvement in many patients[citation needed]. Intense pulsed light has also been effective in the treatment of melasma [3]. Dermal melasma is generally unresponsive to most treatments, and has only been found to lighten with products containing mandelic acid (such as Triluma cream) or Fraxel laser.

In all of these treatments the effects are gradual and a strict avoidance of sunlight is required. The use of broad-spectrum sunscreens with physical blockers, such as titanium dioxide and zinc dioxide is preferred over that with only chemical blockers. This is because UV-A, UV-B and visible lights are all capable of stimulating pigment production.

Cosmetic cover-ups can also be used to reduce the appearance of melasma.

4- Cafe Au Lait

A flat spot on the skin that is the color of coffee with milk (café au lait) in persons with light skin, or a darker appearance (café noir) than the surrounding skin in persons with dark skin. About 10% of the general population have cafe au lait spots, and they can be removed with a Yag laser. Café au lait spots are in themselves harmless, but in some cases they may be a sign of neurofibromatosis. The presence of 6 or more café au lait spots each of which is 1.5 centimeters or more in diameter is diagnostic of neurofibromatosis. Conversely, most people with neurofibromatosis who are at least 5 years old have 6 or more cafe au lait spots 1.5 centimeters or more in diameter.

Associated conditions

Neurofibromatosis type I café au lait spot

While café au lait spots do not cause any ailment themselves, having multiple spots has been linked with neurofibromatosis and the rare McCune-Albright syndrome. Specifically, having six or more café au lait spots greater than 5 mm in diameter before puberty, or greater than 15 mm in diameter after puberty, are cardinal diagnostic features of neurofibromatosis type I.

Other syndromes that may include café au lait spots:

Von Hippel – Lindau disease

Fanconi anemia

Tuberous sclerosis

Silver-Russell dwarfism

Ataxia telangiectasia

Bloom syndrome

Basal cell nevus syndrome

Gaucher disease

Chédiak-Higashi syndrome

Hunter syndrome

Marfan's syndrome

Maffucci syndrome

McCune-Albright syndrome

Peutz-Jeghers syndrome

Multiple endocrine neoplasia type 2

A viral disease - Shingles


Shingles


What are Shingles?

Other names: Herpes zoster

Shingles is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. After you have had chickenpox, the virus becomes dormant in your nerve tissue, but it can be reactivated years later as shingles. It is more common in adults between the ages of 60 and 80 and those with weakened immune systems.

Symptoms of shingles include:

Pain, tingling, burning, itching, or numbness in a certain area of the body

Red rash with fluid-filled blisters that start within a week after the pain. The rash typically occurs on one side of your chest. It can also occur on one side of the face or neck.

Fever

Chills

Headache

After the blisters dry up, usually in one to two weeks, pain can persist. Sometimes, shingles can lead to a condition called postherpetic neuralgia, in which sharp, stabbing pain lasts months to years after the rash has disappeared.

Natural Remedies for Shingles

Although natural remedies are promoted for shingles, it is important that you consult a doctor as soon as possible if you think you have shingles, in order to shorten the infection and reduce the risk of complications. This is especially important if the rash appears near the eye area, which can cause temporary or permanent loss of vision.

Although no natural remedies have yet been proven to be effective for shingles, these are some that are being researched or have been used traditionally.

Proteolytic Enzymes

Proteolytic enzymes are enzymes that are produced naturally by the pancreas to help digest protein we eat.

They are also found in certain foods, such as papaya and pineapple. Supplements derived from papaya (called papain), pineapple (called bromelain), and from animal pancreas can be found online, in health food stores, and in some grocery and drug stores.

In a German study, 96 people with shingles took proteolytic enzymes for 14 days and another 96 people with shingles took acyclovir, a standard antiviral medication. Both groups experienced similar pain relief and skin improvement, with the exception of skin redness, which showed greater improvement with the acyclovir treatment. The group taking proteolytic enzymes had significantly fewer side effects.

Side effects of proteolytic enzymes may include digestive upset and allergic reactions. People with allergies to pineapple or papaya should avoid supplements derived from those fruit.

Proteolytic enzymes, particularly bromelain and papain, should not be taken with warfarin (Coumadin), aspirin, or other "blood-thinning" medications as it may increase the effect of the drug. The proteolytic enzyme pancreatin may interfere with the absorption of the vitamin folate.

Tai Chi

There is preliminary evidence suggesting that tai chi may improve immune function and health in older adults at risk for shingles.

In one study, 36 men and women, aged 60 and over, took a 15 week program of Tai Chi Chih (three 45 minute classes per week) or a wait list control. After 15 weeks, there was an increase in varicella zoster virus-specific immunity and health functioning in people taking Tai Chi Chih. Tai Chi Chih is just one form of the Chinese martial art.

Capsaicin Cream

Although you may not have heard of capsaicin (pronounced cap-SAY-sin) before, if you've ever eaten a chili pepper and felt your mouth burn, you know exactly what capsaicin does. Capsaicin is the active ingredient in chili peppers and is sometimes used for postherpetic neuralgia.

In one study, people used either capsaicin cream or a placebo cream. After six weeks, almost 80 percent of people who used the capsaicin cream had significantly greater pain relief compared to people who used the placebo cream.

When it is applied to the skin, capsaicin has been found to deplete substance P--a neurochemical that transmits pain--resulting in an analgesic effect.

Capsaicin cream is also called capsicum cream. It is available in drug stores, health food stores, and online. A typical dosage is 0.025% capsaicin cream applied two to four times a day.

The most common side effect is a stinging or burning sensation in the area. The benefit may take several weeks to develop.

If possible, wear disposable gloves (available at drugstores) before applying the cream. Be careful not to touch the eye area or any areas of broken or sensitive skin.

Antibiotics for Shingles:

Valacyclovir


This shingles antibiotic is converted to acyclovir in the liver. One advantage over acyclovir is that valacyclovir can be dosed three times a day instead of five. It is not available in an intravenous form; however, when taken by mouth, the drug levels are comparable to those achieved with IV acyclovir. "American Family Physician" suggests that valacyclovir may be more effective at decreasing pain levels associated with shingles than acyclovir. Headache, fatigue, depression, nausea, abdominal pain and sore throat are the most common side effects, noted by Drugs.com.


Famciclovir


Famciclovir is another antiviral drug available to treat shingles. It is also administered three times a day by mouth, but at lower doses than acyclovir and valacyclovir. Famciclovir interacts with digoxin by increasing its levels, which may result in toxicity, notes Drugs.com. Headache, nausea, diarrhea and painful menstruation may be seen in people taking famciclovir.


Foscarnet


Foscarnet is an IV antiviral antibiotic sometimes used to treat shingles in cases in which the virus is resistant to acyclovir, according to the University of Maryland Medical Center. This drug can be toxic to the kidneys, but the damage usually heals when the medicine is stopped. It may also cause an imbalance in electrolytes and minerals which could lead to seizures.




Tuesday, September 7, 2010

Aging



DEFINITION OF AGING

Aging is a syndrome of changes that are deleterious, progressive, universal and thus far irreversible. Aging damage occurs to molecules (DNA, proteins, lipids), to cells and to organs. Diseases of old age (diseases which increase in frequency with age, such as arthritis, osteoporosis, heart disease, cancer, Alzheimer's Disease, etc.) are often distinguished from aging per se. But even if the aging process is distinct from the diseases of aging, it is nonetheless true that the damage associated with the aging process increases the probability that diseases of old age will occur.

Some gerontologists prefer to use the word senescence because "aging" implies that the passage of time necessarily results in deterioration (biological entropy) — which is certainly not true during the early, developmental, time of life (before the age of 10 or 12 in humans). I will retain the word "aging" because I believe the association between aging & deterioration is universal as adult years progress and because the distinction between aging & development is very strongly established in conventional language. Also, shorter words make for slightly faster reading.


AGING: CAUSE & CURE

What causes aging? In other words, what lies behind the progressive deterioration that accompanies the passage of time after maturity — with special interest to humans. To answer in outline form:

* METABOLIC DAMAGE

o FREE RADICALS

o GLYCATION

* CELLULAR SENESCENCE & DEATH

o TELOMERE SHORTENING

o DECLINING & INADEQUATE DNA REPAIR & AUTOPHAGY

o DECLINING & INADEQUATE ANTI-OXIDANT DEFENSE

o DEFECTIVE CELL CYCLE CONTROL, PROTEASOMES, LYSOSOMES & HEAT SHOCK PROTEINS

* TOXIC & NON-TOXIC GARBAGE ACCUMULATION

o PROTEIN CROSS-LINKING & AGGREGATION

o ADVANCED GLYCATION END-PRODUCTS (AGEs)

o ATHEROSCLEROTIC AND AMYLOID PLAQUES

o INFLAMMATORY CYTOKINES

o LIPOFUSCIN

o CORTISOL

o METALS

o DDT, PCBs, etc

An organism that can create fewer free-radicals in generating energy (more efficient mitochondria), use less energy to live, have more effective antioxidant defenses, have better DNA protection, have better DNA repair, have a better immune system and detoxify more effectively in the liver — can reduce damage from endogenous & exogenous sources.

Glucose is necessary for energy production, but glucose causes glycation of proteins. Energy creation results in free radicals as a toxic byproduct. Toxic & non-toxic garbage accumulation is primarily a problem for non-dividing cells (like neurons & muscle cells) which cannot dilute-away the garbage. The damage which causes aging is the damage due to necessary metabolism. This damage affects DNA repair, antioxidant production, telomere length, cell-cycle control, proteosome function, etc. — resulting in reduced capacity to cope with increasing levels of damage.

Telomere shortening contributes to mortality only in a few tissues. Neurons & muscle cells are non-dividing and are thus not affected by telomere shortening. Telomere shortening may contribute to mortality most significantly for immune system cells & arterial epithelial cells. Even if telomere shortening in the immune system is proven to cause the majority of deaths in the very elderly, the mortality is better described as "failure of the weakest link" (like the death of wild horses from worn-down teeth) than as aging. If biological gerontologists are successful in finding means to greatly increase human lifespan, then telomere shortening in proliferative tissues may become far more relevant to human aging. (For non-dividing cells, notably neurons, metabolic damage & garbage accumulation could be considered the "weakest link" if it weren't for the fact that cell death is so different from cell senescence.)

Metabolic damage would be much less of a problem if its byproducts (cross-links, AGEs, lipofuscin, etc.) could be eliminated — along with whatever toxins (lead, cadmium, DDT, PCBs, etc.) manage to enter the organism. The so-called immortality of germ cells, bacteria and Hydra is probably due to the diluting-away of toxins (all of the Hydra cells are dividing cells). Lobsters — which have been proposed as candidates for negligible senescence — discard tissue by molting and appear to continue growing without ever maturing. Lobsters express telomerase in all organ tissues and may avoid senescence by the same mechanism as Hydra.

Why does CRAN (Caloric Restriction with Adequate Nutrition) extend lifespan? The most plausible explanation is that the lower level of calorie utilization & energy production allows for lower levels of blood glucose (less glycation) and less free radical production. Efforts to duplicate CRAN with a pill or genetic manipulation probably have no chance of success.

If the "accelerated aging" diseases are a guide, damage to DNA — mitochondrial (mtDNA) and nuclear (nDNA) — are the damage that is most central to aging. Damage to nDNA and nDNA repair capability would be the worst because mitochondria (and mtDNA) can be replaced by lysosome recycling. But the source of that nDNA damage would still be mitochondria. Defective nDNA repair along with associated cell senescence & apoptosis leads more to aging, whereas the nDNA damage itself leads more to cancer. For mtDNA damage, the damage becomes most serious when the lysosomes are no longer capable of removing defective mitochondria which are producing high levels of free radicals. Free radicals are the primary cause of the nDNA and mtDNA damage in the first place. Defective mitochondria play a central role in accelerated apoptosis, leading to tissue degradation. If defective mitochondria which produce high levels of free radicals are the major source of aging damage, then the most effective step towards slowing aging would be improving lysosomal function by providing more efficient enzymes to the lysosomes.

The maximum lifespan of one or a few individuals of a species is taken as a proxy for the rate of aging of that species and for the idea that only extensions of maximum lifespan are relevant to slow aging. But most people die of aging-related diseases: cardiovascular disease, cancer, Alzheimer's Disease, etc. The damaging aging processes that increase vulnerability to these diseases are more relevant to vast majority of people than influences on maximum lifespan. For this reason it is not misleading to speak of diabetes, tobacco, dietary AGEs, ultraviolet radiation and other exogenous sources of tissue damage as accelerating aging — especially when the damage so closely resembles the tissue damage normally associated with aging. For the vast majority of people good genes can only reduce (not prevent) the aging effects of damaging exogenous agents.

The "mechanisms of aging" tend to be quite tissue-specific. Replicative senescence leads to aging of T cells and blood vessel endothelial cells, whereas other forms of cell senescence leads to aging of stem cells in the pancreas and selected areas of the brain. Non-mitotic cells such as neurons and myocytes are more vulnerable to oxidative stress and DNA damage. Glycation leads to cross-linking of extracellular proteins. For any particular individual, the combination of heredity and environmental conditions will cause some tissues and organ systems to age (or experience damage) more than others — and becoming the "weakest link" leading to mortality. The number or individuals who do not succumb to age-related death specific to a particular tissue or organ is a tiny minority.

Until molecular repair technologies are available, good health practices, supplements and organ transplantation are our best hope of bridging the time between now and the Age of Negligible Senescence.

Effects of Aging


Because the digestive system has a lot of reserve built into it, aging has relatively little effect on its function compared to its effects on other organ systems. Nonetheless, aging is a factor in several digestive system disorders. In particular, older adults are more likely to develop diverticulosis and to experience digestive tract disorders (for example, constipation) as a side effect of taking certain drugs.

Esophagus: With age, the strength of esophageal contractions and the tension in the upper esophageal sphincter decrease, but the movement of food is not impaired by these changes. However, many older adults are likely to be affected by diseases that interfere with esophageal contractions.

Stomach: With age, the stomach lining's capacity to resist damage decreases, which in turn may increase the risk of peptic ulcer disease, especially in people who use aspirin and other nonsteroidal anti-inflammatory drugs (NSAIDs). Also with age, the stomach cannot accommodate as much food (because of decreased elasticity), and the rate at which the stomach empties food into the small intestine decreases, but these changes generally do not produce any noticeable symptoms. Aging has little effect on the secretion of stomach juices such as acid and pepsin, but conditions that decrease acid secretion, such as atrophic gastritis, become more common.

Small Intestine: Aging has only minor effects on the structure of the small intestine, so movement of contents through the small intestine and absorption of most nutrients do not change much. However, lactase levels decrease, leading to intolerance of dairy products by many older adults (lactose intolerance). Excessive growth of certain bacteria (bacterial overgrowth) becomes more common with age and can lead to pain, bloating and weight loss. Bacterial overgrowth may also lead to decreased absorption of certain nutrients, such as folic acid, iron, and calcium.

Pancreas, Liver, and Gallbladder: With age, the pancreas decreases in overall weight, and some tissue is replaced by scarring (fibrosis). However, these changes do not decrease the ability of the pancreas to produce digestive enzymes and sodium bicarbonate. As the liver and gallbladder age, a number of structural and microscopic changes occur.

Large Intestine and Rectum: The large intestine does not undergo much change with age. The rectum does enlarge somewhat. Constipation becomes more common. This may be due partly to a slight slowing in the movement of contents through the large intestine and a modest decrease in the contractions of the rectum when filled with stool.