Allergies
The role of humor and laughter in managing allergic reactions has received very little attention from researchers. But the preliminary evidence available suggests that laughter (or the humor that triggers it) may help counteract certain allergies. (It should be noted that stress often increases level of allergic response.150) Again, it is the Japanese researcher Hajime Kimata who has completed several breakthrough studies along these lines. For example, laughter while watching a comedy video has been shown to reduce an allergic skin response in patients with dermatitis (stress increased the allergic response),151 as well as an allergen-specific (a particular kind of Japanese cedar tree) immunoglobulin E response among patients with dermatitis.152
Surprisingly, Dr. Kimata has also shown in more than one study that watching a tear-producing movie also reduces the level allergic response.153 This is reminiscent of the finding that certain types of negative emotion reduce pain, just as humor and laughter do. It is not clear at this point how to interpret these findings when it comes to the role of emotion in supporting wellness. If sadness-inducing experiences and joy-inducing experiences eventually prove to be equally effective in reducing the level of one's allergic response, I - for one - will always go for the funny approach.
Atopic (meaning that it's probably hereditary) eczema (AE) is a common form of chronic allergy-linked dermatitis (inflammation of the skin). Patients who have AE tend to suffer frequent bacteria-induced infections, including infections from Staphylococcus aureus bacteria.154 The use of antibiotics does help battle this disease, but there are concerns that the prolonged use of antibiotics may produce drug-resistant strains of Staphylococcus aureus. Given the evidence just discussed documenting the positive impact of humor and laughter upon certain types of allergic response, along with the evidence reviewed earlier showing a generalized immunoenhancement effect resulting from humor and laughter (including increased scavenging for free radicals), Dr. Kimata speculated that humor and laughter might enhance antimicrobial immunity in other body fluids, as well - including sweat.
He has shown that this is, indeed, the case. AE patients have deficient levels of a peptide called dermcidin, and low levels of dermcidin from sweat glands have been linked to increased colonization of skin bacteria.155 Antimicrobial peptides appear to be derived from dermcidin. Watching a 90 minute comedy film (Charlie Chaplin) significantly increased the levels of dermcidin from these patients' sweat glands.156 Given this promising finding for a single comedy movie, Dr. Kimata had 14 patients with AE watch funny videos daily for one week - with no medication. Patients' dermcidin levels increased and - most importantly - "the number of patients colonized by S. aureus [bacteria] decreased from 14 (before viewing) to 4 (after viewing)." So humor and laughter appear to be very helpful in battling yet another disease condition - apparently as a result of a strengthened or more aroused immune system.
The health benefits of breast feeding for babies have long been known. Dr. Kimata has shown that humor and laughter among breast feeding mothers also help their babies battle at least one kind of allergy. Mothers again watched a 90-minute Charlie Chaplin film (or a non-humorous control film). Breastfed babies with atopic eczema showed reduced levels of allergic skin response (to latex and house dust mite) following viewing of the comedy film (but not the control film).157 The reason for this effect is not clear, but Dr. Kimata did note that the laughter increased levels of melatonin in mothers' breast milk. Melatonin is a hormone that has been associated with relaxation, and people with eczema generally have low levels of it.
Dr. Kimata's guess at this point is that the relaxation effect resulting from laughter is responsible for the increased melatonin levels following the funny film, and that the increase in melatonin reduces allergic responses by "inhibiting mast cell responses." (Mast cells are large cells in connective tissue that contain substances that mediate allergic reactions.) As with the new asthma-humor research, these initial findings hold exciting promise for yet another wellness-promoting benefit of humor and laughter. More research along these lines is sure to follow in the near future.
Diabetes
The rapidly increasing prevalence of diabetes in the U.S. is well documented. The health risk of diabetes, of course, occurs when blood glucose levels get dangerously high. People with diabetes are unable to naturally produce the appropriate levels of insulin required for the body to use the glucose present in the blood, causing blood sugar to get too high. If not managed well, persistent high glucose levels can lead to circulatory problems (sometimes resulting in amputation), heart disease, stroke, kidney failure or blindness.
Can humor and laughter help keep blood glucose levels under control - or even reduce the risk of developing diabetes to begin with? While there is no reason to expect humor to be helpful in preventing diabetes, it may be helpful in managing it. A different team of Japanese researchers, led by Dr. Takashi Hayashi, recently became the first to take the plunge into this totally unexplored area by having both healthy individuals and diabetics first listen to a monotonous 40-minute college lecture and then (on a different day) sit in on a 40-minute comedy show (as part of an audience of 1000 people). The healthy and diabetic groups had identical meals prior to attending these events.
Among the healthy subjects, there was no difference between blood glucose levels following the comedy and serious lecture. Among diabetics, however, glucose levels were significantly lower following the comedy show (most subjects in both groups rated themselves as laughing a lot during the comedy presentation). So the laughter (or humor) served to reduce the level of blood glucose increase "in the presence of insufficient insulin action."158 The researchers concluded that "This favorable effect of laughter may include the acceleration of glucose utilization by the muscle action [of laughter] during the comedy show. However, it is possible that positive emotions such as laughter acted on the neuroendocrine system and suppressed the elevation of blood glucose level."
In any case, the researchers suggested that these findings point to "the importance of daily opportunities for laughter in patients with diabetes." (Italics are McGhee's.) This glucose-reducing effect of humor and laughter was subsequently replicated by the same research team.159 It should be noted that it was not determined whether the key to lowering glucose levels was the experience of humor or the laughter that followed. But this finding is especially noteworthy in view of evidence that negative emotion tends to increase blood glucose level.160
The key question here, of course, is what might be responsible for this important glucose-lowering effect of laughter among diabetics. A summary of the researchers' explanation is provided here, but the answer is a highly technical one. There is evidence that what is called the "renin-angiotensin system" may play an important role in diabetes. Renin is an enzyme produced by the kidneys that helps produce angiotensin, a protein that - among other things - causes constriction of blood vessels. This system plays an important role in the maintenance of normal blood pressure and electrolyte balance.161 High blood sugar levels stimulate the production of renin.162 Individuals with diabetes show elevated levels of renin in the blood, and this elevated renin appears to be associated with microvascular problems in diabetics.163 These vascular complications often occur in the kidney, retina (e.g., diabetic retinopathy or blindness) or nervous system. So anything which reduces blood renin levels should reduce these vascular complications and support better health in diabetics.
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This same Japanese research team exposed diabetic patients (all had type 2 diabetes and were not receiving insulin) to a six-month regimen of watching comedy videos once a week. At the beginning of the study, these diabetic subjects' plasma renin concentration was five times higher than that typical of non-diabetics. By the third month of watching comedy videos, this concentration had dropped (on the average) by 2/3, and the drop was maintained into the sixth month. The drop put the renin levels into the normal range for 50% of the participating subjects. The researchers speculated that hormonal changes associated with laughter may play a role in causing these changes. They suggested that the effect of laughter on the endocrine system might be to "suppress the secretion of renin from the kidney and stimulate the synthesis of angiotensinogen from the liver." In any case, the key health benefit for diabetics is the significant drop in renin and its health-damaging potential. The researchers concluded that "laughter therapy can be used as a non-pharmacological treatment for the prevention of diabetic microvascular complications."164
Another potential value of humor in connection with diabetes lies in the nature of the communication between patients and their physician. While medical noncompliance is common in connection with most diseases, it is especially high among diabetics (where complex regimens involving medication, diet and exercise must be followed).165 Many patients do not communicate their lack of compliance with eating guidelines - especially when the communication style adopted by their doctor is an authoritative or negative one.166 Establishing a lighter style (by the doctor) of inquiring about compliance habits helps establish trust in the doctor-patient relationship and may also increase commitment to compliance with established eating regimens.
Impact of Humor and Laughter upon Gene Expression among Diabetics
As the field of mind/body medicine has continued its explosive growth over the past 25 years, the inevitable question of whether one's emotional state (or "mind" in general) can influence the basic expression of one's genes has been raised.167 The same Japanese research team of Takashi Hayashi and his colleagues have obtained the first evidence that humor and laughter can alter gene expression. They studied the effect of humor and laughter on prorenin, a precursor of the kidney enzyme renin. Again using diabetic patients in a design similar to the one discussed above (watching a boring lecture vs. a live comedy show), they found that prorenin levels were significantly higher in diabetic than normal individuals. These levels were not influenced by the comedy show in non-diabetics, but dropped sharply following the comedy viewing in diabetics - including both those who had and had not already suffered some degree of nephropathy (kidney damage).168 This is consistent with the finding discussed in the previous section and supports the notion that diabetic patients would do well to build more humor and laughter into their lives.
Perhaps the most exciting finding from this study was that it demonstrated - for the first time - that humor and laughter are capable of having a direct influence on the expression of one's inherited genes. Initially, ". . . the prorenin receptor gene was less expressed in the patients . . . compared with normal subjects . . . [but] This gene was up-regulated significantly . . . after watching the comedy show."169 The comedy had no significant impact on the expression of this gene in the non-diabetic subjects.
Given the suggestion that a decreased expression of this prorenin receptor gene is to some extent responsible for the increased blood prorenin concentrations that contribute to the exacerbation of diabetes-related problems,170 this ability of laughter to up-regulate the expression of prorenin receptor genes (thereby reducing microvascular complications that accompany diabetes) is clearly an exciting finding. If humor and laughter are capable of influencing gene expression in ways that promote health and wellness in connection with diabetes, it may well be that this is one of the key (but now poorly understood) mechanisms by which humor sustains health in general. This is an area that researchers are sure to tackle in the years ahead.
