Garlic: Contraindications. Practice Points. FAQ

Contraindications and Precautions Patients with bleeding abnormalities should avoid therapeutic doses of garlic. Although usual dietary intakes are likely to be safe prior to major surgery, suspend the use of high-dose garlic supplements 1 week before, as garlic may increase bleeding risk. If being used as part of a topical application, a test patch is advised before more widespread application. Pregnancy Use Garlic is not recommended at doses greater than usual dietary intakes. Practice Points / Patient Counselling • Garlic is both a food and a therapeutic medicine capable of significant and varied pharmacological activity. • It has antioxidant, antimicrobial, antiplatelet, antithrombotic, antihypertensive, lipid-lowering, anti-atherosclerotic and vasoprotective activity. • It also enhances microcirculation and may have hypoglycaemic, anti-inflammatory and immunostimulant activity. • Garlic is used as a treatment for many common infections, to reduce the incidence of colds, improve peripheral circulation and manage hyperlipidaemia and hypertension. • Increased consumption of garlic has been associated with a decreased risk of stomach and colorectal cancer, according to a review of the Read more […]

Garlic: Dosage. Adverse Reactions. Interactions.

Dosage Range GENERAL GUIDE • Fresh garlic: 2-5 g/day (ensure it is bruised, crushed or chewed). • Dried powder: 0.4-1.2 g/day. • Aged-garlic extracts have been studied in amounts ranging from 2.4 to 7.2 g/day. • Oil: 2-5 mg/day. • Garlic preparations that will provide 4-12 mg alliin daily. • Fluid extract (1:1): 0.5-2 mL three times daily. ACCORDING TO CLINICAL STUDIES • Hypertension: 600-900 mg/day in divided doses (delivering approximately 5000-6000 µg allicin potential). • Hyperlipidaemia: 600-9000 mg/day. • Fungal infection: topical 0.4-0.6% ajoene cream applied twice daily. • Occlusive arterial disease: 600-800 mg/day. It is important to be aware of the thiosulfinate content, in particular allicin-releasing ability, of any commercial product to ensure efficacy. Adverse Reactions INTERNAL USE Breath and body odour, allergic reactions, nausea, heartburn, flatulence, abdominal discomfort and diarrhea have been reported. Headache, myalgia and fatigue were reported in one study using a dose of 900 mg garlic powder (standardised to 1.3% alliin). TOPICAL USE An ajoene 0.6% gel produces a transient burning sensation after application, according to one study. Contact Read more […]

Garlic: Uses

Clinical Use Most studies have used a non-enteric coated dehydrated garlic powder preparation standardised to 1.3% alliin content (Kwai, Lichtwer Pharma) or an aged garlic extract (Kyolic, Wakunaga of America). CARDIOVASCULAR DISEASE Epidemiologic studies show an inverse correlation between garlic consumption and progression of CVD in general. This review will consider the evidence for garlic in the management of specific risk factors such as hypertension and hyperlipidaemia. Additionally, investigation into the effects of garlic directly on the atherosclerotic and arteriosclerotic processes is presented. Hypertension A meta-analysis of seven clinical trials using a garlic preparation, produced commercially as Kwai, found that three showed a significant reduction in SBP and four in DBP. Kwai was used in these studies in the dosage of 600-900 mg daily. Garlic treatment resulted in a mean reduction in SBP of 7.7 mmHg and 5.0 mmHg in DBP compared with placebo. In 2000, the Agency for Health Care Research and Quality analysed results from 27 randomised, placebo-controlled trials and reported that results were mixed. When significant reductions in blood pressure were observed, these were small. Several newer Read more […]

Garlic: Background. Actions

Historical Note Garlic has been used as both a food and a medicine since antiquity. Legend has it that garlic was used in ancient Egypt to increase workers’ resistance to infection and later used externallyto prevent wound infection. Other ancient civilizations have also used it medicinally. Sanskrit records document the use of garlic approximately 5000 years ago and the Chinese have been using it for over 3000 years. One of the uses of garlic was as a treatment for tumours, a use which extends back to the Egyptian Codex Ebers of 1550 BC. Louis Pasteur was one of the first scientists to confirm that garlic had antimicrobial properties. Garlic was used to prevent gangrene and treat infection in both world wars. Traditionally, garlic has been used as a warming and blood cleansing herb to prevent and treat colds and flu, coughs, menstrual pain and expel worms and other parasites. Common Name Garlic Other Names Ail, ajo, allium, camphor of the poor, da-suan, knoblauch, la-juan, poor man’s treacle, rustic treacle, stinking rose Botanical Name / Family Allium sativum (family Liliaceae) Plant Part Used Bulb, and oil from the bulb Chemical Components Garlic bulbs contain organosulfur compounds, protein (mainly alliinase), Read more […]

Selenium: Practice Points – Patient Counselling. FAQ

Selenium is a trace element that is essential for health. • Low selenium states have been associated with a variety of conditions, such as cardiovascular disease, cancer, asthma, atopy, male subfertility, rheumatoid arthritis, depression and anxiety and compromised immune function. • Studies have identified selenium deficiency in a significant number of people with the HIV infection and suggested a link between selenium levels and mortality rate. • It is also involved in the detoxification of some heavy metals and xenobiotics. • Selenium-enriched yeast is the safest way to supplement the diet, but other forms are also used. Answers to Patients’ Frequently Asked Questions What will this supplement do for me? Selenium supplementation may reduce the risk of developing certain cancers and heart disease and help to improve a range of conditions such as rheumatoid arthritis, asthma, autoimmune thyroiditis, male subfertility, depression and anxiety. When will it start to work? If a protective effect is to occur with selenium against cancer or cardiovascular disease, the effect appears to develop slowly over several years’ consistent intake. Are there any safety issues? High intakes Read more […]

Selenium: Adverse Reactions. Interactions. Pregnancy Use.

Toxicity Long-term ingestion of excessive levels of selenium (> 1000 µg/day) may produce fatigue, depression, arthritis, hair or fingernail loss, garlicky breath or body odour and gastrointestinal disorders or irritability. Adverse Reactions Nausea, vomiting, nail changes, irritability and fatigue have been reported. The organic form of selenium found in high-selenium yeast is often preferred because it is less toxic. The National Health and Medical Research Council of Australia states that selenium intake should not exceed 600 µg/day. Significant Interactions CISPLATIN Selenium may reduce associated nephrotoxicity, myeloid suppression and weight loss, according to in vitro and in vivo tests — beneficial interaction. HEAVY METALS (E.G. MERCURY, LEAD, ARSENIC, SILVER AND CADMIUM) Selenium reduces toxicity of heavy metals such as mercury, lead, arsenic, silver and cadmium by forming inert complexes — beneficial interaction. Contraindications and Precautions Sensitivity to selenium. Pregnancy Use Considered safe in usual dietary doses; safety at higher levels is unknown.

Selenium: Clinical Use. Dosage

DEFICIENCY STATES: PREVENTION AND TREATMENT Traditionally, selenium supplementation has been used to treat deficiency or prevent deficiency in conditions such as malabsorption syndromes. CANCER: PREVENTION AND POSSIBLE ADJUNCT TO TREATMENT Selenium supplementation is used to reduce total cancer incidence and mortality. Chemoprevention Collectively, geographical studies, epidemiological data, laboratory bioassays, studies in over 12 different animal models and human intervention trials generally support a protective role for selenium against the development of cancer. Populations who live in low selenium environments and have low selenium intakes tend to have higher cancer mortality rates. However, the results from epidemiological studies have been less consistent and show the effect is strongest in males. Total cancer incidence and mortality The Nutritional Prevention of Cancer Trial was a large multicentre, double-blind, randomised, placebo-controlled trial conducted with 1312 patients with a history of basal cell or squamous cell carcinomas of the skin, which investigated the effects of 200 µg selenium daily (as 500 mg brewer’s yeast) as a cancer protective agent. Selenium supplementation in this population Read more […]

Selenium: Actions

ANTIOXIDANT Selenium is an integral part of thioredoxin reductase and the glutathione peroxidases and therefore is intimately involved in the body’s antioxidant systems. These enzymes are involved in controlling tissue levels of free radical molecules and maintain cell-mediated immunity. CHEMOPREVENTATIVE Chemoprotective effects of selenium have been indicated by an epidemiological relationship, RCTs and by experimental studies of selenium and known carcinogens in the development of specific cell lines. Overall, it appears that selenium works by inhibiting important early steps in carcinogenesis. Several mechanisms have been postulated to explain the chemopreventative effect of selenium, including protection against oxidative damage, alterations to immune and metabolic systems, alterations to carcinogen metabolism, production of cytotoxic selenium metabolites, inhibition of protein synthesis, stabilisation of genetic material and stimulation of apoptosis. One study demonstrated that combining vitamin E succinate and methylselenic acid produces a synergistic effect on cell growth suppression, primarily mediated by augmenting apoptosis. In humans, the chemopreventative effect is strongest for individuals with Read more […]

Selenium: Background. Deficiency Signs and Symptoms

Background and Relevant Pharmacokinetics Selenium is an essential trace element that enters the food chain through incorporation into plants from the soil. Selenium is mainly present in the form of selenite in acid soils, which is poorly assimilated by crops, whereas for alkaline soils, it is in the form of selenate, which is more soluble and assimilated by crops. When taken in supplement form, animal and human trials demonstrate that bioavailability of organic forms of selenium (Se-methionine and Se-cysteine) is higher than that obtained for inorganic forms (selenite and selenate). The variation in selenium content of adult humans living in different parts of the world is testimony to the influence of the natural environment on the selenium content of soils, crops and human tissues. According to a WHO report, adults in New Zealand have approximately 3 mg selenium in their bodies compared with 14 mg in some Americans (WHO 2002). Selenium is readily absorbed, especially in the duodenum but also in the caecum and colon. Vitamins A, E, and C can modulate selenium absorption, and there is a complex relationship between selenium and vitamin E that has not been entirely elucidated for humans. Selenium enters the body Read more […]