What is magnesium
Magnesium is a catalyst for more than 300 enzyme systems that control a variety of biological reactions in the body, including protein synthesis, muscle and nerve function, blood sugar control, and metabolic processes. The magnesium content in the serum is less than 1% of the total magnesium, and this concentration is strictly controlled. Normal blood calcium concentration ranges from 0.75 to 0.95 millimoles (mmol)/L. Hypomagnesemia was defined as a serum magnesium value less than 0.75 mmol/L. Assessing magnesium status is difficult because most magnesium is found in cells or bones. The most common and easiest way to assess magnesium status is to measure serum magnesium concentration, although serum magnesium levels have little correlation with systemic or tissue magnesium levels. Other methods of assessing magnesium status include measuring magnesium in red blood cells, saliva, and urine; measuring the concentration of magnesium ions in blood, plasma or serum; then perform a magnesium loading (or "thinking") test. Some experts (but not others) believe that the tolerance test (measurement of urine magnesium after injecting a main dose of magnesium) is the best way to assess the status. magnesium in adults. To fully assess magnesium status, laboratory testing and clinical evaluation may be necessary.
Recommended intake
The Dietary Reference Intake (DRI) established by the Food and Nutrition Board (FNB) of the Institute of Medicine of the National Academy of Sciences (formerly the National Academy of Sciences) provides recommendations for the intake of magnesium and other nutrients . DRI is a general term for a set of reference values used to plan and evaluate the nutritional intake of healthy people. These values vary by age and gender, and include:
- Recommended Dietary Intake (RDA): The average daily intake is sufficient to meet the nutritional needs of almost all (97%–98%) healthy individuals; it is usually used to plan a nutritious diet for individuals.
- Adequate intake (AI): It is assumed that this level of intake will ensure adequate nutrition; this is true when there is insufficient evidence to establish an RDA.
- Estimated Average Requirement (EAR): The average daily intake that is estimated to meet the needs of 50% of healthy individuals; it is usually used to assess the nutritional intake of a population and plan a nutritious diet for them; it can also be used to assess the nutritional intake of individuals.入量。 Into the amount.
- Tolerable maximum intake (UL): The maximum daily intake is unlikely to cause adverse health effects.
Source of Magnesium
FOOD
In general, foods that contain dietary fiber can provide magnesium. Certain types of food processing, such as refining grains by removing the germ and bran, can significantly reduce magnesium content. About 30 to 40 percent of dietary magnesium is absorbed by the body.
DIETARY SUPPLEMENTS
Magnesium supplements are available in various forms, including magnesium oxide, citrate, and magnesium chloride. Small studies have shown that aspartate, citric acid, lactic acid, and other forms of magnesium are more absorbable and more bioavailable than magnesium oxide and magnesium sulfate. One study found that consuming very high doses of zinc (142 mg/day) from supplements can interfere with magnesium absorption and disrupt magnesium balance in the body.
DRUG
(Although this dose of magnesium is well above the safe upper limit, some of the magnesium is not absorbed due to the drug's laxative effect.) Magnesium is used to treat heartburn and upset stomach caused by acidic indigestion. It is also included in some medicines used for. For example, Extra Strength Rolaids® provide 55 mg of elemental magnesium (as magnesium hydroxide) per tablet, while Tums® contain no magnesium.
Magnesium intake and status
In a study using 2003-2006 NHANES data to assess mineral intake in adults, dietary supplement users had a higher mean magnesium intake than food alone (350 mg for men and 267 mg for women, equal to or less than the EAR intake) ) was higher than non-users (men 268 mg, women 234 mg). When supplements were included, the average magnesium intake was 449 mg for men and 387 mg for women, above the EAR level.
There is currently no data on the status of magnesium in the United States. Determining dietary magnesium intake is a common indicator for evaluating magnesium status. Since 1974, NHANES has not determined the serum magnesium levels of its participants , and magnesium has not been evaluated in routine electrolyte tests in hospitals and clinics .
Magnesium deficiency
In otherwise healthy people, symptomatic magnesium deficiency due to low dietary intake is not common because the kidneys restrict the urinary excretion of this mineral . However, low or excessive loss of magnesium due to certain health conditions, chronic alcoholism, and/or the use of certain drugs can lead to magnesium deficiency.
Early signs of magnesium deficiency include loss of appetite, nausea, vomiting, fatigue, and weakness. As the magnesium deficiency worsens, there may be numbness, tingling, muscle contractions and cramps, seizures, personality changes, abnormal heart rhythms, and coronary artery spasms . Severe magnesium deficiency can lead to hypocalcemia or hypokalemia (low serum calcium or potassium levels, respectively) because mineral homeostasis is disrupted .
Groups at risk of magnesium deficiency
Magnesium deficiency occurs when the intake is lower than the RDA but higher than the amount needed to prevent a significant deficiency. The following populations are more likely to be at risk of magnesium deficiency than others because they usually consume insufficient amounts or their medical conditions (or taking medications) reduce the absorption of magnesium in the intestines or increase the loss of magnesium in the body.
PEOPLE WITH GASTROINTESTINAL DISORDERS
Chronic diarrhea and fat malabsorption caused by Crohn's disease, gluten-sensitive enteropathy (celiac disease), and regional enteritis can lead to magnesium consumption over time . Removal or bypassing of the small intestine, especially the ileum, usually results in malabsorption and loss of magnesium .
TYPE 2 DIABETES PATIENTS
Patients with insulin resistance and/or type 2 diabetes may experience magnesium deficiency and increased urinary magnesium excretion . Magnesium loss appears to be secondary to a higher concentration of glucose in the kidneys, which increases urine output .
PEOPLE WITH ALCOHOL DEPENDENCE
Magnesium deficiency is common in patients with chronic alcoholism . In these people, poor dietary intake and nutritional status; gastrointestinal problems, including vomiting, diarrhea, and steatorrhea (fatty stools) caused by pancreatitis; renal insufficiency, excessive excretion of magnesium in the urine; phosphate Depletion; vitamin D deficiency; acute alcoholic ketoacidosis; and hyperaldosteronism secondary to liver disease may all cause a decrease in magnesium status .
THE ELDERLY
The dietary magnesium intake of the elderly is lower than that of the young . In addition, with age, the absorption of magnesium in the intestines will decrease, while the excretion of magnesium by the kidneys will increase . Older people are also more likely to suffer from chronic diseases or take medications that change magnesium status, which increases their risk of magnesium consumption .
Magnesium and health
Habitual intake of low magnesium can lead to changes in biochemical pathways, which will increase the risk of disease over time. This section focuses on four diseases and disorders that magnesium may be involved in: hypertension and cardiovascular disease, type 2 diabetes, osteoporosis, and migraine.
HYPERTENSION AND CARDIOVASCULAR DISEASE
A meta-analysis of 12 clinical trials found that magnesium supplementation for 8 to 26 weeks in 545 hypertensive participants resulted in a modest reduction in diastolic blood pressure (2.2 mmHg). The authors of another meta-analysis of 22 studies involving 1,173 adults with normal blood pressure and hypertension found that magnesium supplementation for 3 to 24 weeks can reduce systolic blood pressure by 3 to 4 mmHg and diastolic blood pressure by 2 to 3 mmHg. then stop The Community Atherosclerosis Risk Study assessed cardiovascular risk factors and serum calcium levels in 14,232 African American men and women aged 45 to 64 years. Over a 12-year follow-up period, compared with people in the lowest quartile, people in the highest quartile of the physiological range of serum magnesium (at least 0.88 mmol/L) had a 38% lower risk of cardiac death sudden . . Another study of 88,375 nurses in the United States determined whether serum magnesium levels measured at the beginning of the study and magnesium intake from food and supplements were assessed every 2 or 4 years, according to a study after 26 years. It is associated with sudden cardiac death during labor. Compared with women with very low plasma levels of nitrogen and magnesium, the risk of sudden cardiac death in women with very high intakes was 34% and 77%, respectively. Another population-based study in the Netherlands of 7,664 cancer-free adults aged 20 to 75 years found that low urinary magnesium intake (an indicator of low magnesium dietary intake) is associated with an increased risk of ischemic heart disease. The mandate is 10.5 years. Plasma calcium levels are not related to the risk of ischemic heart disease. The following systematic review and meta-analysis of studies found that higher levels of serum calcium were associated with a lower risk of cardiovascular disease and a higher calcium intake (up to 250 mg per day) is less likely. of cardiovascular diseases. High intake of magnesium may reduce the risk of stroke. A large, well-designed clinical trial is needed to better understand the contribution of magnesium in food and supplements to heart health and the primary prevention of cardiovascular disease.
TYPE 2 DIABETES
A meta-analysis of seven of these studies (including 286,668 patients and 10,912 diabetic patients with 6 to 17 years of follow-up) found that for every 100 mg/day increase in total magnesium intake, the risk of diabetes was significantly reduced. Another meta-analysis of 8 prospective cohort studies followed 271,869 men and women between the ages of 4 and 18 and found a significant negative correlation between food intake of magnesium and the risk of type 2 diabetes ; When comparing the highest and lowest intakes, the relative risk is reduced by 23% . A 2011 meta-analysis of prospective cohort studies on the association between magnesium intake and the risk of type 2 diabetes included 13 studies with a total of 536,318 participants and 24,516 cases of diabetes . Researchers found that there was a dose-responsive negative correlation between magnesium intake and the risk of type 2 diabetes, but this association only reached statistical significance in overweight (body mass index [BMI] 25 or higher), and in normal weight Individual (BMI below 25). For example, in a clinical trial in Brazil, 128 patients with poorly controlled diabetes received a placebo or a supplement containing 500 mg/day or 1,000 mg/day of magnesium oxide (providing 300 or 600 mg of elemental magnesium, respectively) . After taking the supplement for 30 days, participants who took higher doses of the supplement had increased plasma, cellular, and urinary magnesium levels and improved blood sugar control. In another small trial in Mexico, participants with type 2 diabetes and hypomagnesemia received liquid magnesium chloride supplements (providing 300 mg of elemental magnesium per day) for 16 weeks to participants who received a placebo. Fasting blood glucose and glycated hemoglobin concentration were: Decreased significantly and serum magnesium levels remained normal. However, in 50 patients with type 2 diabetes taking insulin, supplementing with magnesium aspartate (which provides 369 mg of elemental magnesium per day) and taking a placebo for three months had no effect on blood glucose control. The American Diabetes Association states that there is insufficient evidence to support the use of magnesium to improve blood sugar control in people with diabetes.
OSTEOPOROSIS
Magnesium participates in bone formation and affects the activities of osteoblasts and osteoclasts . Magnesium also affects the concentration of the active form of parathyroid hormone and vitamin D, which are the main regulators of bone homeostasis. Several population-based studies have found that there is a positive correlation between the magnesium intake of men and women and bone mineral density . Other studies have found that women with osteoporosis have lower serum magnesium levels than women with osteopenia and women without osteoporosis or osteopenia . These and other findings suggest that magnesium deficiency may be a risk factor for osteoporosis .
Although the number is limited, studies have shown that increasing the intake of magnesium from food or supplements may increase bone mineral density in postmenopausal and elderly women . For example, a short-term study found that compared with placebo, 20 postmenopausal women with osteoporosis taking 290 mg/day of elemental magnesium (such as magnesium citrate) for 30 consecutive days can inhibit bone turnover, which indicates that bone quality Loss is reduced .
A diet that provides recommended levels of magnesium can enhance bone health, but further research is needed to clarify the role of magnesium in the prevention and management of osteoporosis.
MIGRAINE
Magnesium deficiency is related to factors that induce headaches, including neurotransmitter release and vasoconstriction . The serum and tissue magnesium levels of migraine patients are lower than those of patients without migraine.
However, research on the use of magnesium supplements to prevent or reduce migraine symptoms is limited. Three of four small, short-term, placebo-controlled trials found that the frequency of migraines was moderately reduced in patients given magnesium up to 600 mg/day . The authors of the migraine prevention review recommend that 300 mg of magnesium taken twice a day, alone or in combination with medications, can prevent migraine .
In their updated evidence-based guidelines, the American Academy of Neurology and the American Headache Society concluded that magnesium therapy "may be effective" in preventing migraine . Since the typical dose of magnesium used to prevent migraines exceeds UL, this treatment can only be used under the guidance and supervision of a healthcare provider.
Health hazards of excessive magnesium
However, high doses of magnesium in dietary supplements or medications can cause diarrhea, as well as nausea and bloating. Magnesium supplements and antacids (most providing more than 5,000 mg/day of magnesium) have been associated with magnesium toxicity, including fatal hypermagnesemia in 28-month-old boys and senior citizens. Symptoms of magnesium toxicity usually occur after the serum concentration exceeds 1.74-2.61 mmol/L, including hypotension, nausea, vomiting, and flushing. of the eye, urinary retention, intestinal obstruction, depression, fatigue, etc., progressing to muscle weakness, dyspnea and Very heavy. Hypotension Blood pressure, cardiac arrhythmias and cardiac arrest.
Interaction with drugs
Several types of drugs may interact with magnesium supplements or affect magnesium status. Some examples are provided below. People who take these and other medications on a regular basis should discuss their magnesium intake with their healthcare provider.
BISPHOSPHONATE
Supplements or medications rich in magnesium can reduce the absorption of oral bisphosphonates used to treat osteoporosis, such as alendronate (Fosamax®) . Use magnesium-rich supplements or medications and oral bisphosphonates should be separated by at least 2 hours .
ANTIBIOTIC
Magnesium can form insoluble complexes with tetracyclines (such as demecycline (Declomycin®) and doxycycline (Vibramycin®)) and quinolone antibiotics (such as ciprofloxacin (Cipro®) and levofloxacin (Levaquin®)). These antibiotics should be taken at least 2 hours before or 4-6 hours after taking magnesium supplements .
DIURETICS
Chronic treatment with loop diuretics (such as furosemide (Lasix®) and bumetanide (Bumex®)) and thiazide diuretics (such as hydrochlorothiazide (Aquazide H®) and acetonitrile (Edecrin®)) increases urine Loss of magnesium and lead in the liquid magnesium consumption . In contrast, potassium-sparing diuretics, such as amiloride (Midamor®) and spironolactone (Aldactone®), can reduce magnesium excretion .
PROTON PUMP INHIBITOR
Prescription proton pump inhibitor (PPI) drugs, such as esomeprazole magnesium (Nexium®) and lansoprazole (Prevacid®), can cause hypomagnesemia when taken for a long time (usually more than a year) . Under FDA review, magnesium supplements usually increase the low serum magnesium levels caused by PPI. However, in 25% of cases, supplements did not increase magnesium levels and patients had to stop PPI. The FDA recommends that healthcare professionals consider measuring the serum magnesium levels of patients before beginning long-term PPI treatment and regularly check the magnesium levels of these patients .
