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How can we tell if someone is experiencing “too much” oxidative stress? Much as criminals may leave “fingerprints” at the scene of a crime, free radicals leave a trail of cellular damage that can be detected as fragments of damaged lipids, proteins, and DNA. We can look for these “damage indicator fragments” in breath, blood, and urine (Figure 3). Bioindicators of oxidative stress can be used to establish the need for additional dietary antioxidants as well as the optimal intake of these antioxidants (Halliwell 1999). Elevated levels of these bioindicators usually mean that the body needs “reinforcements” in its battle against free radicals. These “reinforcements” are usually dietary antioxidants that can come from food or from antioxidant supplements.

Figure 3—Bio-indicators of oxidative stress.

The Forest Service has recognized that physical fitness and diet are important components of maintaining firefighter health and safety (Sharkey 1997b). Wildland firefighters expend large quantities of energy in an environment containing atmospheric pollutants from burning vegetative material. They may experience intermittent or altered dietary patterns while fighting fires. Research involving occupational specialties that share oxidative stress risk factors similar to firefighters (a diet low in fruits and vegetables, high levels of physical exertion, sunlight exposure, and smoke inhalation) leads us to predict that firefighters may also experience increased free radical formation and therefore might benefit from antioxidant supplementation (Figure 4). Certain types of military training are similar to the rigors of wildland firefighting. Preliminary studies of U.S. Army Ranger training and U.S. Marine Mountain Warfare training indicate that these individuals may be under increased levels of oxidative stress and might benefit from supplemental antioxidants (Shippee 1999, Pfeiffer et al. 1999, Chao et al. 1999).

Figure 4—Are firefighters at increased risk for oxidative stress?

Research is needed to establish if wildland firefighters are indeed under excessive levels of oxidative stress and to investigate their response to supplemental antioxidants. Until such research can be accomplished, it is advisable to take a conservative approach that includes both diet and exercise as preventive measures (Table 4). As recommended in the USDA Forest Service report, “Fitness and Work Capacity” (Sharkey 1997b), firefighters should be in excellent physical condition, participate in regular aerobic and strength training, and pay close attention to their diet. These steps will ensure high levels of antioxidant defense enzymes and nutrients in their tissues. Their normal diet should include at least five servings of fruits and vegetables each day. During extended periods of training or actual firefighting, the catering service should be encouraged to supply foods that contain high levels of antioxidant nutrients. Fruits, fruit juices, and vegetable juices are appealing to most people even under adverse field conditions and are good sources of antioxidant nutrients. Serious consideration should be given to providing supplemental antioxidants during field training and firefighting. These supplements could be provided in beverage or tablet form. The potential for antioxidant supplementation to cause harm is low. Supplementation has significant potential short- and long-term benefits. A possible exception may be heavy cigarette smokers, who should avoid supplements containing high levels of beta carotene, due to its association with increased risk of cancer (Diplock 1997).

Table 4—Recommendations to lower oxidative
stress levels in firefighters.

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