Цинк и иммунная система: полное руководство

Цинк необходим для развития и функционирования Т-лимфоцитов и других иммунных клеток. Его дефицит снижает иммунный ответ и делает организм более уязвимым к инфекциям.

Устрицы (лидер по содержанию цинка), говядина, семена тыквы, кешью, бобовые, цельные зёрна и молочные продукты. Растительные источники усваиваются хуже из-за фитатов.

Взрослым мужчинам нужно 11 мг, женщинам — 8 мг в день. Признаки дефицита: частые простуды, медленное заживление ран, потеря аппетита, выпадение волос.

Добавки цинка полезны при подтверждённом дефиците или повышенном риске (вегетарианцы, пожилые люди, люди с хроническими заболеваниями ЖКТ). Не превышайте 40 мг в день — избыток цинка может навредить иммунитету и снизить усвоение меди.

Zinc supplements come in several different salt forms with varying elemental zinc content and bioavailability. Zinc gluconate and zinc acetate are among the most bioavailable forms and are commonly used in lozenges and capsules. Zinc citrate and zinc picolinate also have good bioavailability and are well tolerated. Zinc oxide has lower bioavailability but is widely used in fortified foods. Zinc sulphate is the least expensive option but more likely to cause gastrointestinal side effects. Standard supplemental doses for immune support and general nutrition typically range from 8–15mg of elemental zinc daily, which aligns with RDA levels (8mg for adult women, 11mg for adult men). Therapeutic doses for clinical deficiency may range from 25–50mg daily under medical supervision. An important consideration with zinc supplementation is its interaction with copper: zinc and copper compete for absorption via the same intestinal transporters, and sustained high-dose zinc supplementation will deplete copper over time, potentially causing anaemia and neurological symptoms. Any supplementation exceeding 25mg of elemental zinc daily should include copper at a ratio of approximately 10:1 (zinc to copper). Zinc also competes with iron for absorption, so iron supplements should not be taken simultaneously. Certain medications including quinolone and tetracycline antibiotics, penicillamine, and some diuretics interact with zinc and should not be co-administered. For most adults eating a varied diet that includes some animal protein, targeted attention to zinc-rich foods is sufficient; supplements are most warranted for strict vegans, older adults, those with malabsorptive conditions, and people under physiological stress from surgery or illness.

Zinc's relevance to male reproductive and hormonal health has attracted significant research attention. The testes contain some of the highest concentrations of zinc in the body, and zinc is required for testosterone biosynthesis, sperm production, and sperm DNA integrity. The enzyme 5-alpha-reductase — which converts testosterone to the more potent dihydrotestosterone — is zinc-dependent. Zinc also inhibits aromatase, the enzyme that converts testosterone to oestrogen, meaning that adequate zinc status helps maintain a favourable testosterone-to-oestrogen ratio. Studies in zinc-deficient men consistently show reduced testosterone levels, and supplementation in deficient individuals reliably raises serum testosterone. A landmark study published in Nutrition found that dietary zinc restriction in healthy young men produced a significant decrease in serum testosterone after 20 weeks, while zinc supplementation in borderline-deficient elderly men more than doubled their testosterone concentrations. The effect of zinc supplementation on testosterone in men who are already zinc-sufficient appears to be minimal — consistent with the broader pattern in zinc research that benefits are concentrated in those with genuine insufficiency. Beyond testosterone, zinc is a structural component of the zinc-finger proteins that regulate sperm chromatin packaging, and zinc deficiency is associated with sperm DNA fragmentation and reduced fertility. In the prostate — the tissue with the highest zinc concentration in the body — zinc plays a role in cell apoptosis and appears to have protective effects against malignant transformation. Men's daily zinc requirements are higher than women's (11mg vs 8mg RDA) partly because of the continuous demands of spermatogenesis.