Every thirty minutes, a person dies in an alcohol related car accident. Alcohol is the most common addictive substance used in the US, according to the National Council on Alcoholism and Drug Dependence (1). Alcoholism continues to create great burdens in societies throughout the world due to its cost or the consequences brought to families suffering from its abuse. It has a toll on people of every race, gender, age, and ethnicity. Social and moderate drinkers justify their habit by stating that a few drinks would even be good for health, yet they do not realize that their habit could lead to a destructive future addiction. In a world where alcohol is viewed as a necessity for social gatherings and environments, it is easy to overlook the risks associated with its consumption.

Research studies have shown that alcohol drinking significantly increases the risk of developing cancers throughout the body. With at least fifteen carcinogenic compounds such as ethanol, acetaldehyde, arsenic, benzene, formaldehyde, aflatoxins, (2), alcohol can have a direct carcinogenic effect on gastrointestinal cancers through indirect effects by over-expression of oncogenes in cells that trigger cancer development. In addition to a carcinogen effect, it also has a co-carcinogen effect by boosting carcinogenic properties of chemicals (3).

Upon consumption, ethanol is oxidized by bodily enzymes to form acetaldehyde, a very toxic product, during alcohol metabolism (2). High level concentrations of acetaldehyde trigger mucosal hyperproliferation when in contact with the mucosal layer of the digestive tract (4). Alcohol also causes common diseases referred directly by its name such as; alcoholic cirrhosis (alcohol is the most common causative factor of cirrhosis), alcoholic liver disease, alcoholic steatohepatitis, alcoholic cardiomyopathy, alcohol induced chronic pancreatitis, alcoholic hypoglycemia, alcoholic neuropathy, alcoholic anemia, alcoholic dementia, alcohol induced depression and seizures, etc. A beneficial effect of alcohol is that it is one of the agents which can increase the level of good cholesterol called high density lipoprotein (HDL). On the other hand it also deteriorates hypertension and leads to alcoholic cardiomyopathy with its toxicity. The question then is, “Is it safe for a person to use a toxin due to its only one beneficial effect although it is the most common factor of many diseases that are referred directly by its name?” Considering even beyond the organic effects, alcohol can also harm our relationships and cause legal problems such as driving while drunk or intoxicated.

Recently, Bagnardi et al. (5) reported a meta-analysis about alcohol drinking and cancer in a medical journal, the Annals of Oncology, showing that alcohol consumption even in small amounts increases the risk of oral cavity, pharynx, esophagus, larynx, liver, breast, and colo-rectum cancers. Most of the data derives from studies of moderate to high alcohol intake. For the first time, the researchers evaluated the association between light alcohol drinking (even 1 drink daily) and cancers by evaluating 13,814 non-unique papers identified through literature search. 222 unique papers were included in the meta-analysis, comprising ~92,000 light drinkers and 60,000 non-drinkers with cancer. Most notably, even light drinking was associated with the risk of oropharyngeal cancer, esophageal squamous cell cancer, and female breast cancer (5). These findings show that even though some findings have suggested health benefits for light alcohol consumption, risk of cancer increases with any sort of alcohol consumption.

Previously, there was some support that light consumption of alcohol – one glass for women and two glasses for men – might improve cholesterol levels, lower the risk of forming blood clots, decrease inflammation, and increase antioxidant activity. However, this mere suggestion has quickly been generalized to the overall public. Potential benefits of light drinking depends on the patients’ age, general health, lifestyle, nutrition, history of alcoholism, and many other factors. According to research evidence, any amount of alcohol consumption poses and increases the risk of alcohol linked cancer (6). Because alcohol consumption is a modifiable risk factor for cancer and many diseases, the more a person consumes alcohol products, the greater the risks are (7). These risks are also lowered by reduction in alcohol consumption; thus there is no truly “safe” level of alcohol intake (6).

Alcohol reduces the blood levels of vitamins A and E, zinc, iron and some B vitamins, including folate and thiamin, leading to vitamin deficiency, nutritional disorders, and toxicities, all of which can trigger cancer development. Alcohol suppresses the immune system and makes alcoholics more susceptible to developing cancer (8). Considering these data, drinking alcohol for older people has no potential benefits. The risk-to-benefit ratio is a little higher in younger individuals, as they have higher rates of binge drinking and acute intoxication.

The sensitive question to consider is: should individuals consciously poison themselves if they think that a toxin might have a potential beneficial effect? Can a clinician recommend a toxic drug use for its effect on nausea? For alcohol, the evidence of harmful effects is stronger than evidence of the beneficial effects (6). There are many other proven safer ways of maintaining our heart health on track, without any risk of alcohol-related hypertension, stroke, coronary artery disease, diabetes, congestive heart failure, cancer, dementia, violence, or accidents.

Then, why is alcohol so praised nowadays? The alcohol industry tries to maintain and endorse alcohol consumption. In some countries, alcohol production is very high and is an important element in the economy. Public health has a very powerful opponent known as the alcohol industry; Bagnardi et al. (5) have reported a meta-analysis published against the alcohol industry and their enormous power against public health.

Even light drinking practice may turn many vulnerable people into alcoholics. Alcoholism is a prodigious defect behind many physiological and psychological problems, not only in individuals but also within many families and societies. It can also result in drunk driving accidents, which claim thousands of lives in the US every year. One simply cannot become an alcoholic if they do not drink. It would be beneficial to have people re-think their stance about this real toxin to fight against alcohol abuse and dependence.

Tahan is a student at the College of Sciences, University of Iowa.

References

1) https://ncadd.org/for-the-media/alcohol-a-drug-information

2) Lacshenmeier DW, Przybylski MC, Rehm J. Comparative risk assessment of carcinogens in alcoholic beverages using the margin of exposure approach. Int J Cancer. 2012; 131(6):E995-1003.

3) Haas SL1, Ye W, Löhr JM. Alcohol consumption and digestive tract cancer. Curr Opin Clin Nutr Metab Care. 2012;15(5):457-67.

4) Homann N, Kärkkäinen P, Koivisto T, Nosova T, Jokelainen K, Salaspuro M. Effects of acetaldehyde on cell regeneration and differentiation of the upper gastrointestinal tract mucosa. J Natl Cancer Inst. 1997 Nov 19; 89(22):1692-7.

5) Bagnardi V, Rota M, Botteri E, Tramacere I, Islami F, Fedirko V, Scotti L, Jenab M, Turati F, Pasquali E, Pelucchi C, Bellocco R, Negri E, Corrao G, Rehm J, Boffetta P, La Vecchia C. Light alcohol drinking and cancer: a meta-analysis. Ann Oncol. 2013; 24(2):301-8.

6) http://www.medscape.com/viewarticle/824237

7) Holman DM, Grossman M, Henley SJ, Peipins LA, Tison L, White MC. Opportunities for cancer prevention during midlife: highlights from a meeting of experts. Am J Prev Med. 2014; 46(3 Suppl 1):S73-80.

8) Pericleous M1, Mandair D, Caplin ME. Diet and supplements and their impact on colorectal cancer. J Gastrointest Oncol. 2013; 4(4):409-23.

Southern Pine Beetles (Dendroctonus frontalis, figure 1) are one of the most harmful pests in the world, causing hundreds of million dollars worth of damage to pine trees in the Southern United States. These beetles initiate their attack on a pine tree by having a small group of female beetles dig into the inner park (Figure 2) and phloem of the pine tree. Once this work is done these females will secrete a chemical that will draw other male and female beetles to the affected pine tree. This initial attack is followed by a massive attack by a larger number of beetles, enabling them to easily overcome the defenses of the pine trees due to the sheer number of beetles. Shortly after taking over the tree, mating begins between the male and female beetles. As part of the mating process the females fill the excavated galleries within the trees with eggs. After the eggs have been laid the adult beetles will then leave the tree and continue to attack other trees. Attacking trees and causing their death is of course a sad story and may not sound very interesting since most pests have similar attack strategies; however, one detail that we did not mention yet makes this process more intriguing. What do the larvae eat to complete their development within a gallery that is inside a dead tree? The answer is: Fungi.

Pine beetles establish a symbiotic life structure with a beneficial fungus (Entomocorticium sp. A), which is the main food source for their larvae. Adult pine beetles have a body compartment (mycangium), in which they can carry this fungus. When adult beetles dig galleries in tree barks, they inoculate these galleries with the fungi. This fungus will grow in these galleries that helps the beetles’ larvae complete their development by providing them with a source of nutrition. Fungi also benefit from this process by being transferred from one tree to another with the help of the beetles. This symbiotic life structure is threatened by the existence of an antagonistic fungus, (Ophiostoma minus, also known as blue stain fungus) and parasitic mites both of which the southern pine beetles also bring along. The blue stain fungus has no nutritional importance for larvae, this fungus can grow in the same galleries as the beneficial fungus and they can even outcompete them. In addition, the parasitic mites feed on the blue fungi and can prove harmful beetles as the amount of blue fungi increases. Therefore, beetles’ larvae cannot survive for long and thus the reproduction of the southern pine beetles can be disrupted without some form of defense.

A recent study by Scott et al. has shed some light on this complicated life structure [3]. These tiny beetles, which are only a few millimeters long, have a smart defense mechanism to prevent their larvae (Figure 3, pink arrow). As far as the history tells us, humankind started using pesticides about 5000 years ago, but these tiny beetles have been using them for preventing the growth of the blue-stain fungi long before humans started using pesticides. These studies showed that the symbiotic coexistence of southern pine beetles and the beneficial fungi (Figure 3, yellow circle) is maintained by a (actinomycetous) bacterium (Figure 3, inside the red square). This bacterium produces a previously unknown antibiotic compound (named mycangimycin), which selectively inhibits the growth of blue-stain fungus hence providing a significant advantage for the maintenance of the beneficial fungi (that is, the main food source of the larvae). How can this bacterium even be present in the freshly carved galleries in pine trees in the first place? The surprising answer to this question is that they are transferred to these galleries by the very same pine beetles. As mentioned earlier, adult pine beetles carry beneficial fungi in their body compartment (mycangium) and inoculate the galleries they carved with this fungus to provide food for their larvae. In addition to this beneficial fungi these beetles carry they also carry bacteria that can produce antibiotic compound to inhibit the growth of blue-stain fungi and consequently diminish the number of parasitic mites. This bacterium can grow inside these galleries and even in a body compartment of adult southern pine beetles. Interestingly, this antibiotic kills blue-stain fungi but does not significantly affect the growth of the fungi, which is the food source for larvae. Thus, the beneficial fungi can multiply in number and offer enough food for the development of beetle larvae. Some of these larvae manage to grow to adults and then leave to attack other pine trees carrying the same fungi and bacteria with them (Figure 4).

The interactions within the rest of the life kingdoms is not any less complicated than the symbiosis between pine beetles, fungi, and the bacteria. The interactions between animals, plants and microbes are very complex and also fragile. Removing or replacing any member of an ecosystem can often result in a serious failure in the ecosystem as was observed many times especially within the last century.

References

1. http://www.nsf.gov/news/news_summ.jsp?org=NSF&cntn_id=112319&preview=false.
2. http://entnem.ufl.edu/creatures/trees/southern_pine_beetle.htm.
3. Scott, J.J., et al., “Bacterial protection of beetle-fungus mutualism.” Science, 2008. 322 (5898): p. 63.