Beginning in childhood, ADHD is one of the most commonly diagnosed psychiatric disorders in children and adolescents. ADHD becomes apparent in some children in the preschool and early school years.
ADHD is thought to affect about 9.2% of boys and 2.9% of girls who are of school age.
While it is estimated that about 4.4% of adults also suffer from ADHD, the condition often goes unrecognized in adults. It is believed that around 60% of children diagnosed with ADHD retain the disorder as adults.
Adults with ADHD are diagnosed under the same criteria, including the stipulation that their symptoms must have been present prior to the age of seven.
ADHD is divided into three subtypes based on symptoms including inattentive type, hyperactive-impulsive type, and combined type with both inattention and hyperactivity-impulsiveness.
The most common ADHD subtype is the combined type; females are more likely to have the inattentive type.
Heredity: ADHD tends to run in families. About one in four children with ADHD have at least one relative with the disorder, and when one identical twin has ADHD, the other twin almost always has it as well.
Diet: Recent studies have found that children with ADHD may have vitamin and mineral deficiencies. Decreases in zinc, essential fatty acids, iron, B-vitamins, and glyconutrients have been reported in children with ADHD. Protein deficiencies may also contribute to the development of ADHD.
Food and additive allergies: Food allergies (including wheat, soy, corn, dairy, shellfish, nuts from trees such as walnuts, and peanuts) and food additives (such as dyes and preservatives) have been reported to aggravate the symptoms of ADHD.
Heavy metal toxicity and other environmental toxins: Environmental toxins (chemicals) and heavy metal (including lead, mercury, and cadmium) exposure during pregnancy or in childhood may contribute to the development of ADHD. Smoking during pregnancy has been reported to increase the chances of developing ADHD.
Violence, abuse and other emotional traumas: While no conclusive evidence has been offered that parenting methods can cause ADHD in otherwise normal children, some clinicians believe this is the case.
The exact cause of ADHD remains unknown. Most of the causes have been reported to be dysfunction in the brain and nervous system.
Altered brain function: Dopamine is a brain neurochemical necessary for proper function. Research has found that individuals with ADHD may have a deficiency of dopamine. Also, individuals with ADHD may have decreased blood flow to the brain.
Thyroid disorders: Thyroid abnormalities have been associated with ADHD and other childhood psychiatric disorders.
Head injuries: Head trauma in childhood may cause neurological problems leading to the development of ADHD.
Drugs: Hyperactivity may be caused by high or repeated doses of caffeine or stimulants.
Genetics: People with family histories of ADHD have an increased risk of developing this disorder. This is because genetics has been linked to many cases of ADHD. Scientists are studying several genes that may be involved in ADHD.
Because people with ADHD generally have lower levels of the brain chemical dopamine, researchers are interested in learning more about the genes involved in dopamine regulation. Strong evidence suggests that the dopamine D4 receptor (DRD4) gene is involved in ADHD. A specific variation in this gene may increase a person's risk of developing ADHD by 13-19%. In a meta-analysis, researchers found that some variations dramatically increased the risk of ADHD, while other variants may have a protective effect. Other research suggests that variants of the dopamine D5 receptor (DRD5) gene may significantly increase the risk of ADHD. Yet, one variation of DRD5 may help prevent ADHD.
Researchers are also studying the dopamine transporter (DAT1, also known as SLC6A3) gene mainly because it provides instructions for making the dopamine transporter protein. This protein binds to dopamine, removing it from the tiny space between nerve cells (called the synaptic cleft) and deposits it to nearby cells. Some variations in the DAT1 gene have been linked to ADHD, although evidence of this association is not as strong as the DRD4 and DRD5 genes.
Some studies have focused on the dopamine beta-hydroxylase gene (DBH) gene. This gene provides instructions for making the dopamine beta-hydroxylase protein which breaks down dopamine into norepinephrine, thereby affecting the total level of dopamine in the brain. Studies in this area have produced conflicting results, and it is unclear if variations of the DBH gene play a role in ADHD.
Variations in the serotonin transporter (SLC6A4) gene have also been studied in relation to ADHD. However, the role of SLC6A4 in ADHD remains unclear.
The synaptosomal-associated protein 25 (SNAP-25) gene may also play a role in ADHD. In animal studies, mice with a particular variation in the (SNAP-25) gene exhibited hyperactive behavior and other signs of ADHD. However, research in this area has been conflicting.
SIGNS AND SYMPTOMS
Individuals with ADHD have many symptoms, including extreme inattentiveness and/or impulsiveness and hyperactivity. Many people with ADHD continue to have symptoms throughout life. The symptoms of ADHD fall into the following two broad categories.
Inattention: Symptoms of inattention include failure to pay close attention to details, trouble keeping focused during play or tasks, appearing not to listen when spoken to, failure to follow instructions or finish tasks, avoiding tasks that require a high amount of mental effort and organization such as school projects, frequently losing items required to facilitate tasks or activities such as school supplies, excessive distractibility, forgetfulness, procrastination, inability to begin an activity, difficulties with household activities (cleaning, paying bills, etc.), difficulty falling asleep, frequent emotional outbursts, easily frustrated, and easily distracted.
Hyperactivity-impulsive behavior: Hyperactive-impulsive symptoms include fidgeting with hands or feet or squirming in seat, leaving seat often even when inappropriate, running or climbing at inappropriate times, difficulty in quiet play, frequently feeling restless, excessive speech, answering a question before the speaker has finished, failure to wait one's turn, interrupting the activities of others at inappropriate times, and impulsive spending leading to financial difficulties.
A positive diagnosis is usually only made if the person has experienced six of the above signs and symptoms for at least three months. Symptoms must appear consistently in varied environments (not only at home or school) and interfere with general functioning.
Children who grow up with ADHD often continue to have signs and symptoms as they grow into adulthood. Adults living with ADHD may experience challenges in the areas of self-control, self-motivation, and decision making as well as depression, anxiety and substance abuse. Adults may have more signs and symptoms of inattention and less of hyperactivity-impulsive behavior than children.
Diagnosis of ADHD is mainly based on observed symptoms and behavior.
Clinical testing: The American Academy of Pediatrics Clinical Practice Guideline for children with ADHD states that a diagnosis should be based upon the following three criteria:
1. The use of explicit criteria for the diagnosis using the DSM-IV-TR (Diagnostic Criteria of Mental Disorders: the clinical reference for psychiatric illnesses). The Conners' Rating Scale is commonly used.
2. The importance of obtaining information about the child's symptoms in more than one setting. This is completed by obtaining a personal medical and family history from parents, teachers, and the patient.
3. The search for coexisting conditions that may make the diagnosis more difficult or complicate treatment planning. This is done with psychological and intelligence testing.
Analytical testing: Some clinicians use brain scan technology to determine if there is a problem with brain function or blood flow. These tests include MRI (Magnetic Resonance Imaging), PET (Positron Emission Tomography), and SPECT (Single Photon Emission Computed Tomography). Scientists have concluded, however, that there is not enough evidence to use these methods to determine if an individual has ADHD.
Computerized tests: These generally determine the attention span of the individual. However, due to a high rate of false negatives, this testing modality is not commonly used to determine if an individual has ADHD.
Individuals with ADHD struggle to function normally in daily life. Children often struggle in the classroom, which can lead to academic failure and ridicule from other children and adults.
Children with ADHD are much more likely to experience minor trauma, such as fractures and cuts, than are other children. Adults and teenagers are also more likely to become involved in car accidents and have other injuries. Individuals with ADHD may also be more likely to have trouble with following the law and commit crimes.
As many as one in three children with ADHD also have other psychological or developmental conditions.
Oppositional defiant disorder (ODD): Generally defined as a pattern of negative, defiant and hostile behavior toward authority figures, ODD tends to occur more frequently in children who are impulsive and hyperactive and is especially common in boys.
Conduct disorder: A more serious condition than ODD, conduct disorder is marked by distinctly antisocial behavior such as stealing, fighting, destroying property, harming people and animals, and committing crimes. Children with conduct disorder need immediate help.
Depression: Depression may occur in both children and adults with ADHD. It's more likely to appear when there is a family history of depression.
Anxiety disorders: Anxiety disorders tend to occur fairly often in children with ADHD and may cause overwhelming worry and nervousness as well as physical signs and symptoms, such as a rapid heartbeat, sweating and dizziness. Although anxiety disorders can cause severe symptoms, most people can be helped with therapy or medication. Once anxiety is under control, children are better able to deal with the problems arising from ADHD.
Learning disabilities: Children with both ADHD and learning disabilities are the children most in need of special education services.
Tourette's syndrome: Many children with ADHD are at increased risk of Tourette's syndrome, a neurological disorder characterized by compulsive muscular or vocal tics.
Alcohol and drug abuse: Individuals with ADHD may be more likely to develop addiction problems with alcohol or drugs, due to factors including altered brain function and the continued use of stimulants.
Family therapy: Family therapy can help parents and siblings deal with the stress of living with a child who has ADHD.
Behavioral therapy (BT): BT helps individuals with ADHD develop more effective ways to work on immediate issues. Practical assistance may be offered such as helping organize school tasks and studying for school, or assisting the individual with powerful emotional issues. Anger control is an example of BT.
Psychotherapy: Psychotherapists work to help people with ADHD to live as functioning members of society, increasing self-esteem and dealing with other psychological issues. Psychotherapy alone, however, does not address the symptoms or underlying causes of the disorder. Upsetting thoughts and feelings are verbalized, along with exploration of self-defeating patterns of behavior. Individuals with ADHD can learn alternative ways to handle their emotions.
Social skills training: Social relationships are studied with a therapist to help the individual with ADHD develop and maintain social relationships, like waiting for a turn, sharing toys, asking for help, or responding to teasing. Social skills training helps the child to develop better ways to play and work with other children, and provides the adult with better social skills.
Support groups: Support groups help individuals with ADHD and parents to connect with other people who have similar problems and concerns. Meetings occur on a regular basis (usually weekly) to share frustrations and successes and to hear lectures from experts on ADHD, obtain referrals to qualified specialists and information about what works.
Parenting skills training: Parents face special obstacles when raising a child with ADHD, and often feel frustrated and like there is no help. Parenting skills training is offered by therapists or in special classes, and can give parents tools and techniques for managing their child's behavior. Time outs, reward systems, and organization are just a few of the skills taught.
Stimulants: The most frequently prescribed medications for ADHD are stimulants, which work by stimulating the areas of the brain responsible for focus, attention, and impulse control. Stimulant drugs include Methylphenidate (Ritalinï¿½, Metadateï¿½, Focalinï¿½, Concertaï¿½, Daytranaï¿½ - a topical methylphenidate patch), amphetamine, mixed salts (Adderallï¿½, Adderall XRï¿½), dextroamphetamine (Dexedrineï¿½), modafinil (Provigilï¿½), methamphetamine (Desoxynï¿½), and the recently approved lisdexamfetamine (Vyvanseï¿½).
Atomoxetine (Stratteraï¿½) is a norepinephrine reuptake inhibitor and helps regulate brain function. Atmoxetine is usually taken once or twice a day, depending on the individual, every day, and takes up to 6 weeks to begin working fully.
Amantadine (Symmetrelï¿½) is used to increase dopamine in the brain. Reports suggest that low-dose amantadine has been successfully used off label to treat ADHD.
Antidepressant medications may be used off label for ADHD, including serotonin reuptake inhibitors (SSRIs), monoamine oxidase inhibitors (MAOIs, including selegiline (Emsamï¿½)), and bupropion (Wellbutrinï¿½).
Good scientific evidence:
Zinc: One study has shown a correlation between low serum free fatty acids and zinc serum levels in children with attention deficit hyperactivity disorder (ADHD). Two other studies found that zinc supplements reduced hyperactive, impulsive and impaired socialization symptoms, but did not reduce attention deficiency symptoms. Zinc supplementation may be a more effective treatment for older children with higher body mass index (BMI) scores. Zinc is generally considered safe when taken at the recommended dosages. Avoid zinc chloride since studies have not been done on its safety or effectiveness. Avoid with kidney disease. Use cautiously if pregnant or breastfeeding.
Unclear or conflicting scientific evidence:
Bach flower remedies: Little clinical information is available on the effects of Bach flower remedies on attention deficit hyperactivity disorder, although one subjective test found that it has no significant effect. More research confirming these results is necessary before a conclusion can be made. Back flower remedies should not be used in lieu of more proven therapies.
Flaxseed and flaxseed oil (Linum usitatissimum): Preliminary evidence supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to attention deficit hyperactivity disorder (ADHD). Based on preliminary clinical evidence, alpha linolenic acid-rich nutritional supplementation in the form of flaxseed oil may improve symptoms of ADHD. More research is needed to confirm these results.
Flaxseed has been well-tolerated in studies for up to four months. Avoid if allergic to flaxseed, flaxseed oil or other plants of the Linaceae family. Avoid large amounts of flaxseed by mouth and mix with plenty of water or liquid. Avoid flaxseed (not flaxseed oil) with a history of esophageal stricture, ileus, gastrointestinal stricture or bowel obstruction. Avoid with a history of acute or chronic diarrhea, irritable bowel syndrome, diverticulitis or inflammatory bowel disease. Avoid topical flaxseed in open wounds or abraded skin surfaces. Use cautiously with a history of a bleeding disorder or with drugs that cause bleeding risk (like anticoagulants and non-steroidal anti-inflammatories (like aspirin, warfarin, Advilï¿½), high triglyceride levels, diabetes, mania, seizures or asthma. Avoid if pregnant or breastfeeding. Avoid with prostate cancer, breast cancer, uterine cancer or endometriosis. Avoid ingestion of immature flaxseed pods.
Gamma linolenic acid (GLA): Clinical trials investigating the effect of GLA on symptoms associated with attention deficit hyperactivity disorder are limited. There is no evidence of effectiveness of treatment with GLA, but more study is needed to confirm these results. Use cautiously with drugs that increase the risk of bleeding like anticoagulants and anti-platelet drugs. Avoid if pregnant or breastfeeding.
Ginseng: Early small studies suggest that American ginseng may help treat attention deficit hyperactivity disorder (ADHD) in children. However, there is currently not enough evidence to support this use of ginseng. Avoid ginseng with a known allergy to plants in the Araliaceae family. There has been a report of a serious life-threatening skin reaction, possibly caused by contaminants in ginseng formulations.
Glyconutrients: Glyconutrients are supplements that contain monosaccharides (sugar-type molecules), which are required for the synthesis of glycoproteins (help form hormones and immune system components). The effect of a glyconutritional product has been investigated in children with attention deficit hyperactivity disorder (ADHD). A decrease in the number and severity of symptoms was noted. Use cautiously with iron supplements, with history of copper deficiency or a history of vitamin B12 deficiency. There is a lack of human evidence on the use of glyconutrients during pregnancy or breastfeeding.
Iron: Based on preliminary data, taking iron orally might improve symptoms of attention deficit-hyperactivity disorder (ADHD). A recent study found a 3-year-old child with ADHD and low iron levels improved significantly on ADHD testing scores after an eight month treatment with ferrous sulfate, 80 milligrams daily. Caution should be used when taking iron supplements as drug interactions are possible. Iron is a trace mineral, and hypersensitivity is unlikely. Avoid with a known allergy/hypersensitivity to products containing iron. Avoid excessive intake. Avoid iron supplements with blood disorders that require frequent blood transfusions. Use iron supplement cautiously with a history of kidney disease, intestinal disease, peptic ulcer disease, enteritis, colitis, pancreatitis, hepatitis, alcoholism, or in those who plan to become pregnant, are over age 55, or have a family history of heart disease. Pregnant or breastfeeding women should consult a healthcare professional before beginning iron supplementation.
L-carnitine: One study has reported positive effects of using L-carnitine (also called acetyl-L-carnitine) supplements in children (boys) with ADHD. Acetyl-L-carnitine is an antioxidant and may help blood flow as well as neurological function. Avoid with known allergy or hypersensitivity to carnitine. Use cautiously with peripheral vascular disease, hypertension (high blood pressure), alcohol-induced liver cirrhosis, and diabetes. Use cautiously in low birth weight infants and individuals on hemodialysis. Use cautiously if taking anticoagulants (blood thinners), beta-blockers, or calcium channel blockers. Avoid if pregnant or breastfeeding.
Massage: Preliminary research suggests that massage therapy may improve mood and behavior in children with attention deficit-hyperactivity disorder (ADHD). Avoid with bleeding disorders, low platelet counts, or if on blood-thinning medications (such as heparin or warfarin/Coumadinï¿½). Areas should not be massaged where there are fractures, weakened bones from osteoporosis or cancer, open/healing skin wounds, skin infections, recent surgery, or blood clots. Use cautiously with a history of physical abuse or if pregnant or breastfeeding. Massage should not be used as a substitute for more proven therapies for medical conditions. Massage should not cause pain to the patient.
Melatonin: There is some research on the use of melatonin in children with attention deficit-hyperactivity disorder (ADHD) both in the treatment of ADHD and insomnia in ADHD children. Melatonin is not to be used for extended periods of time. Interactions with drugs may occur.
Music therapy: Music has been shown to induce relaxation and may cause reduced heart rate, reduced blood pressure, reduced tension, and many other beneficial changes. Evidence that music therapy can lead to the relaxation response has been found in healthy individuals and individuals with health problems. More study is needed in the area of attention deficit-hyperactivity disorder (ADHD). Music therapy is generally known to be safe.
Pantothenic acid: Pantothenic acid (vitamin B5) is essential to all life and is a component of coenzyme A (CoA), a molecule that is necessary for numerous vital chemical reactions to occur in cells. There is currently insufficient scientific evidence to form a clear conclusion on the use of pantothenic acid for attention deficit-hyperactivity disorder (ADHD). Avoid if allergic or hypersensitive to pantothenic acid or dexpanthenol. Avoid with gastrointestinal blockage. Pantothenic acid is generally considered safe in pregnant and breastfeeding women when taken at recommended doses.
Phenylalanine: DL-phenylalanine has been shown to affect mood after two to four weeks of treatment in adults with attention deficit hyperactivity disorder (ADHD). Additional research is needed in this area. Use cautiously in patients taking monoamine oxidase inhibitors (MAOIs), or in patients with hypertension, anxiety disorders, other psychiatric disorders, or sleep disorders. Avoid in patients with Parkinson's disease or tardive dyskinesia. Avoid in patients with hypersensitivity to phenylalanine or with phenylketonuria (PKU).
Pycnogenolï¿½: Pycnogenolï¿½ is a potent antioxidant that may be effective in decreasing neurological imbalances. Preliminary research comparing Pycnogenolï¿½ vs. placebo in adults with ADHD (Attention Deficient Hyperactivity Disorder) reported improved concentration with both agents. In more recent studies in children, improvements in attention and various rating scales were noted with Pycnogenolï¿½ supplementation. Pycnogenol is considered to be safe in recommended dosages. If pregnant or breastfeeding, consult a qualified health care provider. Avoid if allergic/hypersensitive to pycnogenol, its components, or members of the Pinaceae family. Use cautiously with diabetes, hypoglycemia, bleeding disorders. Use cautiously if taking hypolipidemics, medications that may increase the risk of bleeding, hypertensive medications, or immune stimulating or inhibiting drugs.
Qi gong: There is promising early evidence to support the use of Qi gong in the treatment of attention deficit hyperactivity disorder (ADHD) in children. However, the evidence is currently unclear and further research is needed. Qi gong is generally considered to be safe in most people when learned from a qualified instructor. Use cautiously with psychiatric disorders.
SAMe: S-adenosylmethionine, or SAMe, is formed in the body from the essential amino acid methionine and is used in depression and mood disorders. Preliminary evidence suggests that SAMe may be of benefit for adults with attention deficit hyperactivity disorder (ADHD). Caution should be used when taking SAMe supplements as drug interactions are possible. Use cautiously with diabetes and anxiety disorders. Avoid if allergic or hypersensitive to SAMe. Avoid with bipolar disorder. Avoid during pregnancy or breastfeeding.
Vitamin B6 (Pyridoxine): Some research suggests that pyridoxine supplementation alone or in combination with high doses of other B vitamins may help in the treatment of attention deficit hyperactivity disorder (ADHD). Vitamin B6 may also be found in a multivitamin or a B-complex vitamin supplement. Avoid if sensitive or allergic to any ingredients in vitamin B6 products. Some individuals seem to be particularly sensitive to vitamin B6 and may have problems at lower doses. Avoid excessive dosing. Vitamin B6 is likely safe when used orally in doses not exceeding the recommended dietary allowance (RDA). Use cautiously if pregnant or breastfeeding.
Yoga: There is limited study of yoga in the treatment of attention deficit hyperactivity disorder (ADHD). Further research is needed before a conclusion can be made. Yoga is generally considered to be safe in healthy individuals when practiced appropriately. Avoid some inverted poses with disc disease of the spine, fragile or atherosclerotic neck arteries, risk for blood clots, extremely high or low blood pressure, glaucoma, detachment of the retina, ear problems, severe osteoporosis, or cervical spondylitis. Certain yoga breathing techniques should be avoided in people with heart or lung disease. Use cautiously with a history of psychotic disorders. Yoga techniques are believed to be safe during pregnancy and breastfeeding when practiced under the guidance of expert instruction (the popular Lamaze techniques are based on yogic breathing). However, poses that put pressure on the uterus, such as abdominal twists, should be avoided in pregnancy.
Fair negative scientific evidence:
Evening primrose oil (Oenothera biennis L.): Small human studies show no benefit from evening primrose oil in treatment of attention deficit hyperactivity disorder (ADHD). Further research is needed to make a conclusion.
Phenylalanine: D-phenylalanine lacked efficacy for attention deficit hyperactivity disorder (ADHD) in children at the end of two weeks of treatment in clinical study. Additional research is needed in this area.
Psychotherapy: Psychotherapy may not improve parenting, enhance academic achievement, or improve emotional adjustment for attention deficit hyperactivity disorder (ADHD) in children. It is unclear whether psychotherapy will reduce the use of stimulants, such as methylphenidate, in children with ADHD. More studies are needed in this area.
Traditional or theoretical uses lacking sufficient evidence:
Biofeedback: Biofeedback is often used to help people learn to control certain body responses, such as heart rate and muscle tension. It has also been used with the intent of teaching adults and children with attention deficit hyperactivity disorder (ADHD) to normalize their brain wave patterns. Although biofeedback is generally considered safe, a qualified healthcare professional should be consulted before making decisions about new therapies and/or related health conditions. Biofeedback may interfere with the use of some medications, such as insulin. Behavioral modification therapies should not delay the time to diagnosis or treatment with more proven techniques or therapies, and should not be used as the sole approach to illnesses.
Omega-3 fatty acids: Essential fatty acids have many roles in the body, including proper nerve and brain function. Preliminary evidence supports the idea that deficiencies or imbalances in certain highly unsaturated fatty acids may contribute to attention deficit hyperactivity disorder (ADHD). More research is needed in this area.
Avoid if allergic or hypersensitive to fish, omega-3 fatty acid products that come from fish, nuts, linolenic acid or omega-3 fatty acid products that come from nuts. Avoid during active bleeding. Use cautiously with bleeding disorders, diabetes, low blood pressure or drugs, herbs or supplements that treat any such conditions. Use cautiously before surgery. The Environmental Protection Agency (EPA) recommends that intake be limited in pregnant/nursing women to a single 6-ounce meal per week, and in young children to less than 2 ounces per week. For farm-raised, imported, or marine fish, the U.S. Food and Drug Administration recommends that pregnant/nursing women and young children avoid eating types with higher levels of methylmercury and less than 12 ounces per week of other fish types. Women who might become pregnant are advised to eat 7 ounces or less per week of fish with higher levels of methylmercury or up to 14 ounces per week of fish types with about 0.5 parts per million (such as marlin, orange roughy, red snapper, or fresh tuna).
Nutritional changes along with the addition of supplements (vitamins, minerals and herbs) may be effective in preventing ADHD and improving the symptoms.
Avoid caffeine and other stimulants, alcohol, and smoking.
Eliminate potential food allergens, including dairy (milk, cheese and sour cream), eggs, nuts, shellfish, wheat (gluten), corn, preservatives, and food additives (such as dyes and fillers). Food allergies can be a contributing factor in mental imbalance.
Avoid refined foods such as white breads, pastas, and sugar. Doughnuts, pastries, bread, candy, soft drinks, and foods with high sugar content may all contribute to worsening symptoms of ADHD.
This information has been edited and peer-reviewed by contributors to the Natural Standard Research Collaboration (www.naturalstandard.com).
- American Psychiatric Association. www.psych.org. Accessed March 2, 2009.
- National Alliance on Mental Health. www.nami.org. Accessed March 2, 2009.
- National Institute of Mental Health. www.nimh.nih.gov. Accessed March 2, 2009.
- National Institutes of Health. www.nlm.nih.gov. Accessed March 2, 2009.
- Natural Standard: The Authority on Integrative Medicine. Copyright ï¿½ 2009. www.naturalstandard.com. Accessed March 2, 2009.
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