101 Toxic Food Ingredients
If specific foods are not identified by the clinical history or a diet diary, a hypoallergenic or elimination diet, such as that shown in Table 57-4, may be tried for 2 to 3 weeks. In most cases of suspected GI adverse reactions to foods or food additives, this approach is without benefit because the majority of patients will have functional bowel disease with nonspecific reactions to foods. In cases where a benefit is seen, new foods are gradually introduced in an attempt to identify specific foods that may contribute to the illness. It should be recognized that the hypoallergenic diet can be falsely interpreted as a negative test because a minority of subjects can react to antigens contained in a typically hypoallergenic diet.
Because reactions to food antigens by RAST or skin testing are neither specific nor sensitive, a double-blinded placebo-controlled food challenge (DBPCFC), in which food antigens are administered by nasogastric tube or gelatin capsules, should be performed if possible. This technique is considered the gold standard for diagnosing food allergy but is not widely available. The DBPCFC is also less reliable when assessing for delayed reactions to foods and food additives. Clinical history and the results of skin testing help guide the choice of foods to include in the oral challenge. A number of investigators have performed the GI equivalent of skin testing by injecting the GI mucosa with a panel of antigens and observing for a wheal-and-flare response by endoscopy but this form of testing has not been incorporated into routine clinical practice.
Perhaps the most common form of ARF results from physiologic reactions to food components or additives. It is well known that starches found in legumes serve as substrate for gas production by colonic flora and many other foods are associated with gas, including onions, cabbage, bran fiber, and other vegetables and grains. Certain foods and food additives affect the lower esophageal sphincter, whereas foods high in fat delay gastric emptying, resulting in symptoms of heartburn and dyspepsia. These physiologic reactions to foods are typically noted by patients with functional bowel disease, many of whom exhibit heightened endocrine, motor and sensory responses to normal digestive events. Because elimination of the offending food(s) may provide some benefit in select patients, it is important to determine whether specific food intolerances exist in this group of patients. The reader is referred to
Anaphylactoid or pseudoallergic reactions to food result from foods that mimic the effects of mast cell degranulation but do not involve IgE antibodies. Strawberries and shellfish may cause this type of ARF. Certain food ingredients, including additives such as salicylates, benzoates, and tartrazine, induce pseudoallergic reactions. As with true food allergy, patients exhibiting such reactions should be instructed to avoid the offending food substance if identifiable. Pharmacological reactions to food or food additives represent a relatively common type of ARF, although most of these reactions cause symptoms outside of the GI tract. Histamine found in certain cheeses or in scrombroid fish, such as tuna, can cause headaches and diffuse erythema of the skin. Certain individuals develop migraine headaches to various foodstuffs, including those rich in amines. Sulfites, tartrazine and monosodium glutamate (MSG) have all been associated with asthma, and MSG can cause a characteristic...
The formal characteristics of risk assessment have a brief history (NRC 1994a Rodricks 1992). While many core concepts had been developed earlier, the origins of contemporary risk assessment can be traced to the 1970s when new environmental regulations called for information on risks in order to set policy. Even earlier, however, the need to protect the general public and workers had led to the development of methods for setting exposure limits that inherently involved risk estimation. To protect workers, particularly against short-term toxicity, exposure limits were set that were below levels known or considered likely to have adverse effects. For example, Threshold Limit Values (TLVs) were first set by the American Conference of Government Industrial Hygienists (ACGIH). For foods, acceptable daily intakes (ADIs) of pesticides and food additives were set based on animal assays. The no-observed-effect level (NOEL) in the assay, subsequently modified to the no-observed-adverse-effect...
A radioallergosorbent test (RAST) can be used as an alternative to skin testing in very young children, those with severe atopic dermatitis, those who cannot discontinue antihistamines, and those reporting anaphylactic reactions to foods or food additives. The limitations of RAST are the expense, lower sensitivity, and relatively limited number of antigens that can be tested when compared with skin testing. A modification of the traditional RAST test, the CAP System FEIA (Pharmacia), is reported to be more sensitive than a standard RAST. Levels of food-specific IgE above which a patient has a 95 likelihood of experiencing an allergic reaction after the ingestion of specific food have been established (Sampson, 2002). An oral food challenge is recommended at lower levels of food-specific IgE because the clinical significance of such levels cannot be predicted.
We have seen a few patients whose useless hand was made useful by employing constraint-induced movement therapy. Some third-party payers have denied coverage for these devices and therapies, which is very unfortunate as any element of functional improvement and independence is important for these patients. Speech therapy and communication devices can optimize communication when dysarthria, apraxia of speech, or aphasia is present. Therapists also counsel patients and families on swallowing maneuvers and food additives to minimize aspiration when dys-phagia occurs. Feeding gastrostomy should be discussed with all patients, although many decide not to undergo this procedure.
Chronic paronychia is an inflammatory disorder of the proximal nail fold, typically affecting hands that are continually exposed to a wet environment and repeated minor trauma causing cuticle damage. When the cuticle is torn or lost, the epidermal barrier of the proximal nail fold is impaired and the nail fold is then exposed to a large number of environmental hazards. Irritants and allergens may easily penetrate the proximal nail fold and produce contact dermatitis that is responsible for the chronic inflammation. A variety of immediate hypersensitivity (type I) reaction to food ingredients may be seen. Sometimes irritant reaction may precede it.
Recommend scouring the supermarket aisles (at a time when the patient is not hungry) for tasty, low fat, or fat-free alternatives to favored foods. Encourage the patient to explore the wide variety of foods now available and to focus on the good taste of the new choice rather than comparing it with the real thing. The presentation of nutritional information on food labels is becoming more and more useful, listing not just g of fat, for example, but also the percentage of the daily dietary fat allotment those g represent. The patient should be taught (usually by the dietitian) to read labels and to stay within the fat and calorie budget.
Healthy eating is the cornerstone of diabetic treatment, and control of the diet should always be the first treatment offered to Type 2 diabetic patients before drugs are considered. Eliminating sugar (sucrose and glucose) lowers blood glucose concentrations in both Type 1 and Type 2 diabetic patients, and although recent dietary recommendations suggest that eating small amounts of sugar is of little consequence, this practice is not recommended. Artificial sweeteners can be used. Good dietary advice is essential to the proper care of diabetic patients ill considered advice can be very damaging or else it is ignored. I recall one patient who kept to the same sample menu for many years before she reported it to be rather boring. The diet needs to be tailored to the patient's age and weight, type of work, race, and religion.
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