Results for “antioxidant”
Vitamin C
** Vitamin C (ascorbic acid) is a water‑soluble essential nutrient that supports collagen synthesis, antioxidant defense, neurotransmitter production, and immune function, and must be obtained from the diet by humans and other select species. **CONTENT:** ## Overview Vitamin C, chemically known as **ascorbic acid**, is a small, water‑soluble molecule that humans cannot synthesize because of a mutation in the *GULO* (gulonolactone oxidase) gene. Consequently, we rely on dietary sources—most notably citrus fruits, berries, kiwi, bell peppers, broccoli, and leafy greens—to meet our daily needs. Once absorbed in the small intestine, vitamin C circulates in the plasma and is taken up by cells via sodium‑dependent vitamin C transporters (SVCT1 and SVCT2). Inside cells, it serves as a **cofactor** for several enzymes, most famously those that hydroxylate proline and lysine residues during **collagen** maturation, a process essential for the strength of skin, blood vessels, bone, and connective tissue. Beyond its structural role, vitamin C is a potent **antioxidant**. It donates electrons to neutralize reactive oxygen species (ROS) and regenerates other antioxidants such as vitamin E. In the nervous system, it participates in the biosynthesis of **neurotransmitters** like norepinephrine and serotonin by acting as a cofactor for dopamine β‑hydroxylase. Its influence on the **immune system** includes enhancing the function of phagocytes, supporting epithelial barrier integrity, and modulating cytokine production. While mild deficiencies can lead to scurvy—a disease characterized by bleeding gums, joint pain, and poor wound healing—most people obtain sufficient vitamin C through a balanced diet. However, individuals with malabsorption disorders, chronic smokers, or those on restrictive diets should monitor intake and consider supplementation after consulting a healthcare professional. ## History/Background The story of vitamin C begins with the scourge of **scurvy** among sailors in the 15th–18th centuries. In 1747, James Lind conducted one of the first controlled clinical trials, showing that citrus fruits cured scurvy, a finding that eventually led the British Navy to issue lime juice to its crews—hence the nickname “limey.” The chemical identity of vitamin C remained elusive until 1932, when Hungarian chemist **Albert Szent‑Györgyi** isolated the compound from adrenal glands and named it “ascorbic acid” (a‑scorbic, meaning “no scurvy”). Szent‑Györgyi’s work earned him the Nobel Prize in Physiology or Medicine in 1937. By the 1940s, synthetic production of ascorbic acid became commercially viable, allowing widespread fortification of foods and the launch of the first vitamin C tablets. Research in the latter half of the 20th century expanded the understanding of vitamin C’s antioxidant properties, its role in gene regulation, and its potential therapeutic applications in chronic diseases, though definitive clinical benefits beyond deficiency prevention remain a topic of ongoing investigation. ## Key Information - **Chemical name:** L‑ascorbic acid (C₆H₈O₆) - **Recommended Dietary Allowance (RDA):** 90 mg/day for adult men, 75 mg/day for adult women; higher intakes are advised for smokers (additional 35 mg/day). - **Absorption:** Efficient at low doses (<200 mg); saturates above ~500 mg, with excess excreted in urine. - **Deficiency disease:** **Scurvy**, presenting with fatigue, gingival bleeding, perifollicular hemorrhages, and impaired wound healing. - **Food sources (per 100 g):** Oranges (53 mg), red bell pepper (128 mg), kiwi (93 mg), strawberries (59 mg), broccoli (89 mg). - **Drug interactions:** High-dose vitamin C may increase oxalate kidney stone risk in susceptible individuals and can interfere with certain laboratory tests (e.g., stool guaiac). - **Supplement forms:** Ascorbic acid tablets, buffered mineral ascorbates (e.g., calcium ascorbate), liposomal preparations. - **Safety:** Generally safe up to 2 g/day for most adults; doses above 2 g may cause gastrointestinal upset (diarrhea, abdominal cramps). **When to seek professional care:** If you experience symptoms suggestive of scurvy, have a history of kidney stones, are pregnant or lactating, or are considering high‑dose supplementation (>2 g/day), consult a healthcare provider for personalized guidance. ## Significance Vitamin C’s impact on human health is multifaceted. Its indispensable role in **collagen synthesis** underpins wound healing, dental health, and vascular integrity, making it a cornerstone nutrient for surgeons, athletes, and anyone recovering from injury. As an **antioxidant**, vitamin C helps mitigate oxidative stress implicated in aging, cardiovascular disease, and certain cancers, though clinical trials have yielded mixed results regarding disease prevention. The vitamin’s involvement in **neurotransmitter production** links it to mood regulation and cognitive function, prompting research into its adjunctive use in depression and neurodegenerative disorders. Public health initiatives that promote fruit and vegetable consumption have leveraged vitamin C as a measurable marker of diet quality, contributing to reduced incidence of deficiency diseases worldwide. Moreover, the historical battle against scurvy exemplifies how a single nutrient can transform population health, underscoring the importance of nutrition science in preventive medicine. **INFOBOX:** - **Name:** Vitamin C (L‑ascorbic acid) - **Type:** Water‑soluble vitamin / essential nutrient - **Date:** Isolated in 1932; Nobel Prize awarded 1937 - **Location:** Naturally occurring in fruits, vegetables, and animal adrenal glands; synthesized industrially worldwide - **Known For:** Preventing scurvy, supporting collagen formation, acting as a potent antioxidant **TAGS:** nutrition, vitamins, antioxidant, collagen synthesis, immune function, scurvy, dietary supplement, public health
Health & MedicineAlpha Lipoic Acid
Alpha lipoic acid (ALA) is a naturally occurring organosulfur compound essential for aerobic metabolism, produced in animals and available as a dietary supplement or pharmaceutical drug. ## Overview Alpha lipoic acid (ALA) is a crucial organosulfur compound that plays a vital role in various metabolic processes. It is a naturally occurring compound found in animals, where it is synthesized in the mitochondria, the energy-producing structures within cells. ALA is essential for the proper functioning of the body's energy-producing pathways, including the citric acid cycle and the electron transport chain. As a dietary supplement or pharmaceutical drug, ALA has been used to support various health benefits, including antioxidant properties, improved insulin sensitivity, and enhanced cognitive function. The structure of ALA consists of a sulfur-containing ring, which is responsible for its unique properties. The compound exists in two enantiomers, the (R)-(+)-enantiomer (RLA) and the (S)-(-)-enantiomer (SLA), with RLA being the naturally occurring form. ALA is highly soluble in water and has a relatively low molecular weight, making it easily absorbed by the body. ## History/Background The discovery of ALA dates back to the 1950s, when researchers first isolated the compound from animal tissues. Initially, ALA was thought to be a byproduct of fatty acid metabolism, but further studies revealed its critical role in energy production. In the 1960s, ALA was first synthesized in the laboratory, allowing for its use as a dietary supplement and pharmaceutical drug. Today, ALA is widely available in various forms, including capsules, tablets, and powders. ## Key Information - **Structure:** ALA is an organosulfur compound with a sulfur-containing ring. - **Function:** ALA is essential for aerobic metabolism, serving as a cofactor for various enzymes involved in energy production. - **Forms:** ALA is available as a dietary supplement or pharmaceutical drug, with various forms including capsules, tablets, and powders. - **Absorption:** ALA is highly soluble in water and easily absorbed by the body. - **Enzyme cofactor:** ALA serves as a cofactor for enzymes involved in the citric acid cycle and electron transport chain. - **Antioxidant properties:** ALA has antioxidant properties, helping to protect cells from oxidative damage. - **Insulin sensitivity:** ALA has been shown to improve insulin sensitivity, reducing the risk of developing type 2 diabetes. - **Cognitive function:** ALA has been linked to improved cognitive function and a reduced risk of age-related cognitive decline. ## Significance The significance of ALA lies in its critical role in energy production and its potential health benefits. As a dietary supplement or pharmaceutical drug, ALA has been used to support various health benefits, including antioxidant properties, improved insulin sensitivity, and enhanced cognitive function. ALA's role in energy production makes it essential for maintaining optimal health, particularly in individuals with energy-intensive lifestyles or those at risk of developing metabolic disorders. INFOBOX: - Name: Alpha Lipoic Acid - Type: Organosulfur compound - Date: 1950s (discovery) - Location: Animal tissues - Known For: Essential cofactor for aerobic metabolism and antioxidant properties TAGS: Alpha lipoic acid, organosulfur compound, antioxidant, insulin sensitivity, cognitive function, energy production, citric acid cycle, electron transport chain, dietary supplement, pharmaceutical drug.