Normal IgA levels protect the body against infections, allergies, and autoimmunity. Low levels usually point to a weakened immune system. Read on to learn about the factors that may balance the immune response by increasing IgA levels.
IgA levels are a marker of immune health. Low or high levels don’t necessarily indicate a problem if there are no symptoms or if your doctor tells you not to worry about it.
Improving your IgA levels won’t necessarily directly cause any kind of improvement in immune balance, but it can be used as a biomarker for your immune health.
The following are a list of complementary approaches to improve immune health and that have also been found to improve IgA levels.
Though studies suggest various dietary and lifestyle factors may increase IgA levels, additional large-scale studies are needed. Remember to talk to your doctor before making any major changes to your day-to-day routine.
Supplements that May Improve Immune Health (as Measured by IgA)
1) Probiotics
In a study (DB-RCT) with 47 people, a three-week daily intake of the probiotic L. reuteri increased IgA levels [1].
In 30 athletes, IgA substantially decreased after training in the placebo group, but not in athletes who took L. helveticus (DB-RCT) [2].
Chewing gum containing L. reuteri significantly increased IgA in the saliva (DB-RCT) [3].
Probiotics increased IgA levels and improved recovery in 40 children with burn injuries [4].
In a study (DB-RCT) of 66 pregnant women, high-dose multi-strain probiotics resulted in infants with higher IgA levels and improved gut function [5].
Daily ingestion of L. casei increased IgA levels in 14 subjects [6].
In a study of 98 newborns, B. bifidum increased IgA levels in low birth weight infants [7].
In a study of 413 infants, those who took formula enriched with B. lactis had higher IgA levels that were similar to the levels seen in breastfed infants [8].
The probiotic VSL#3 increased IgA production in monkeys [9].
Gut bacteria may be important for IgA production. Germ-free mice have greatly reduced IgA production in the gut. Even a single strain of bacteria can effectively promote the production of gut IgA in germ-free mice [10, 11].
Probiotics increased IgA production in mice and rats, improved gut function, and protected against inflammation and infection [12, 13, 14, 15, 16, 17].
2) Prebiotics
Prebiotics are food for good bacteria. They improve our gut microbiome.
A prebiotic mixture increased IgA levels and improved metabolic parameters (CRP, insulin, total cholesterol, and triglycerides) in 45 overweight adults (DB-RCT) [18].
In a study (DB-RCT) with 187 infants, those who were exclusively fed formula and given prebiotics had higher IgA levels than infants who received a placebo [19].
Yacon flour, which is 50 – 70% prebiotic fiber, taken for 18 weeks increased IgA in 59 preschool children [20].
Prebiotics increase IgA in rats and mice [21, 22, 23].
A prebiotic taken during pregnancy increased IgA levels in maternal milk in mice [24].
3) Glutamine
A meta-analysis of 13 studies and 1,034 patients concluded that glutamine increased IgA and decreased infectious complications in gut cancer patients [25].
Glutamine increased nasal but not salivary IgA during high-intensity interval training in 13 runners [26].
Glutamine supplementation increased IgA production in the gut of mice and rats [27, 28].
4) Chlorella
Four weeks of chlorella supplementation increased IgA in 15 men [29].
Chlorella also increased resting IgA in 26 subjects in intensive training [30].
Finally, chlorella increased IgA concentrations in breast milk of 18 pregnant women [31].
5) Ginseng
Ginseng enhanced gut IgA production in mice [32, 33, 34].
However, at its higher dosage, it also blocked IgA release [34].
Dietary Factors that May Improve Immune Health (as Measured by IgA)
6) Fasting
In 15 obese subjects, a 14-day fast increased blood IgA levels [35].
Intermittently fasted mice have higher IgA levels and are more resistant to infections [36].
7) Vitamin A
Vitamin A is needed for the transport and release of secretory IgA across the mucosa [37].
Vitamin A-deficient rats and mice have decreased levels of total IgA in the gut, but their blood IgA levels are normal [38].
Breast milk of women supplemented with vitamin A had higher levels of IgA [39].
8) Mushrooms
In 24 volunteers, IgA production increased in those who ate white button mushrooms [40].
White button mushrooms increased IgA in mice [41].
Compounds found in Reishi mushrooms increased IgA in mice [42].
Lifestyle Changes that May Improve Immune Health (as Measured by IgA)
9) Reducing Chronic Stress
Acute stress (lasting a few minutes to a few hours) tends to stimulate the immune response [43].
Examination stress increased IgA levels in 15 nursing students. IgA decreased again two hours after the examination [44].
Contrarily, chronic stress, over a period of several days, weeks or months, decreases the immune response [43].
Chronic stress was associated with lower IgA in middle-aged and elderly subjects [45].
Perceived stress was associated with lower IgA in dental students [46].
In mothers, breast milk IgA was lower in those who experienced more anxiety, depression, anger, fatigue, and confusion [47].
In toddlers attending center or family childcare at home, children with a lower quality of childcare had lower IgA levels [48].
Studies on rodents under stress have also reported a decrease in intestinal IgA [49, 50].
Low IgA is thought to be an important underlying mechanism linking chronic stress with increased upper respiratory tract infections [51].
Managing stress can help reverse the decrease in IgA. A study in 32 women showed that viewing unpleasant pictures decreased IgA levels. However, a reinterpretation of the situation (cognitive reappraisal) reversed the decrease of IgA [52].
10) Relaxation
Directly tied to reducing chronic stress, relaxation techniques can improve immune function and increase IgA levels.
In 24 volunteers, 20 minutes of relaxation significantly increased IgA production. Additionally, those who had practiced relaxation once a day for three weeks had larger increases in IgA levels than those practicing for the first time [53].
Ten minutes of relaxation increased IgA in 79 Japanese female medical workers [54].
In 14 breast cancer patients, IgA was higher after surgery in those who participated in a relaxation method called autogenic training [55].
Thirty minutes of Reiki, an alternative medicine healing technique, caused relaxation and increased IgA levels in 23 subjects [56].
11) Humor
People who use humor as a coping skill have higher baseline IgA levels [57].
Watching a comedy increased IgA in 15 university students and 39 women [58, 59].
Similarly, a funny presentation increased IgA levels in 21 fifth-graders compared to 18 of their classmates who watched an educational presentation [60].
Stressful events decrease IgA levels. Among 40 subjects, those with a sense of humor were less likely to have IgA reduced by stress [61].
12) Music
Listening to music enhanced baseline IgA levels in 87 undergraduate students [62].
Similarly, in a group of 66 college students, those exposed to background music for 30 minutes had increased IgA levels [63].
Another study also showed that college students listening to music had increased IgA [64].
Participating in music may have an even greater effect.
Out of 33 subjects, those who actively sang or played percussions had greater increases in IgA levels than people who only listened to music [65].
Another study showed that singing in the choir increases IgA [66].
13) Short/Moderate Exercise
IgA levels increase in response to short-term or moderate exercise. This can help reduce the risk of respiratory infections [67].
Regular, moderate exercise increased IgA at rest in 9 subjects compared to 10 sedentary controls [68].
Several studies showed that moderate exercise increases IgA in elderly individuals [69, 70, 71].
In 45 elderly individuals, 60-minute resistance and 60-minute moderate endurance training once a week significantly increased IgA after 12 months [72].
14) Avoiding Strenuous Exercise
IgA levels change depending on the intensity and duration of exercise, as well as the type of physical activity. Prolonged exercise decreases, while short-term and moderate exercise increases, IgA levels [73, 74, 75, 76, 68].
Professional athletes have lower IgA levels and are more prone to upper respiratory tract infections [67].
In 155 ultra-marathoners IgA levels decreased after racing [77].
Another study found that IgA also decreased in 64 ultra-marathon racers and 43 participants of an open water swimming race [78].
In soccer players, IgA decreased following training but returned to pre-training levels after 18 hours of rest. Overnight rest was sufficient for IgA recovery following training, but not following two successive matches [79].
In 13 international soccer players, IgA levels progressively declined during a four-day training period [80].
In 26 elite swimmers with a seven-month training season, pretraining salivary IgA levels were 4.1% lower with each additional month of training. Post-training IgA levels were 8.5% lower for each additional 1 km swum in a training session and 7.0% lower for each additional month of training [81].
Adolescent volleyball players had lower IgA levels compared with sedentary volunteers [82].
15) Enough REM Sleep
In a study of 32 volunteers, IgA levels decreased during four nights of REM sleep deprivation, but not after total sleep deprivation. The IgA levels did not return to baseline even after three nights of sleep recovery [83].
Some drugs can block REM sleep and may decrease IgA levels. These include antidepressants and sympathomimetics (drugs that mimic the action of adrenalin and dopamine and activate the sympathetic nervous system) [84, 85].
Salivary IgA increases during sleep. In mice with disrupted circadian rhythms, salivary IgA failed to increase during sleep. It was shown that the increase in IgA was dependent on the sympathetic nervous system (fight-or-flight) activation, which is associated with REM sleep [86, 87].
16) Smoking Cessation
A couple of studies indicated that smoking tobacco and cigarettes can decrease IgA levels.
Tobacco chewers and tobacco smokers had decreased IgA levels compared to nonsmokers. Further, smokers had significantly lower IgA levels than chewers [88].
In mice, three months of cigarette smoke exposure before influenza virus infection resulted in reduced IgA levels and increased lung inflammation [89].
However, some studies showed no differences in IgA levels in smokers [90].
17) Bright Light
In a study of 7 women, exposure to bright light during the day increased IgA levels compared to when they were exposed to dim light [91].
18) Sexual Activity in Moderation
Among 112 college students, those who had frequent sex had the highest IgA levels. The relationship between sexual activity and IgA levels had a reverse ‘U’ shape, with both those having very frequent and infrequent sex having lower IgA levels [92].
These results are conflicting with others that show decreased IgA with sexual activity in women [93, 94].
Further studies will hopefully clarify this point.
19) Breastfeeding (in Babies)
Infants receive IgA via breast milk. Then IgA production in the gut is gradually stimulated by developing gut microbiota [95].
Several studies show that breastfed infants have higher IgA levels [96, 95, 97].
20) Thermal Water Inhalation
Thermal water comes from hot springs. It rises from deep underground and absorbs beneficial minerals on the way to the surface.
In 100 children with respiratory infections, those who inhaled sulfurous thermal water had higher blood IgA and better infection outcomes [98].
In another study, 25 patients treated with thermal water had increased nasal IgA compared to 25 patients treated with distilled water [99].
21) Acupuncture
Acupuncture prevented the decrease in the salivary IgA due to intensive exercise in 12 men [100].
Estrogen
In 86 women, those with higher estradiol (main estrogen) had higher IgA levels [101].
In cell studies, estrogens increase IgA transport into the mucus, which decreases bacterial invasion [102, 103].
Takeaway
Low IgA signals weakened immunity. Studies suggest that certain lifestyle and dietary changes may improve the immune response (and increase IgA levels). Though more research is needed, promising results were seen with probiotics, prebiotics, glutamine, vitamin A, and fasting. Studies suggest that taking up a relaxation technique, avoiding chronic stress, getting enough sleep and moderate exercise, quitting cigarettes, and having a good sense of humor may also strengthen the immune response and increase IgA.
