Allergies

A low-allergy diet, also known as an elimination diet, is often recommended to people with suspected food allergies in order to find out if avoiding common allergen foods gives relief from symptoms. This diet eliminates foods and food additives considered to be common allergens, including nuts.

Cold sores

The herpes simplex virus has a high requirement for the amino acid, arginine. On the other hand, the amino acid lysine inhibits viral replication. Therefore, a diet that is low in arginine and high in lysine might help prevent the herpes simplex virus from replicating. A number of studies have shown that increasing lysine intake can reduce the recurrence rate of cold sores. Although people with herpes simplex infections reportedly consume about the same amount of arginine and lysine in their diet as do people without cold sores, it is conceivable that adjusting the intake of these amino acids might be beneficial. For that reason, many doctors advise people with cold sores to avoid foods high in arginine, such as nuts, particularly peanuts.

Crohn’s disease

In one trial, people with Crohn’s disease were asked which foods aggravated their symptoms. Those without ileostomies (surgical openings that connect the small bowel to a pouch on the outside of the body) found nuts to be among the most problematic foods, though responses varied from person to person. People with Crohn’s disease wishing to identify and avoid potential allergens should consult a doctor.

Eczema

Eczema can be triggered by allergies. Most children with eczema have food allergies, according to data from double-blind trials. A doctor should be consulted to determine whether allergies are a factor. Once the trigger for the allergy has been identified, avoidance of the allergen can lead to significant improvement. Nuts are among the foods considered “classical” food allergens.

Heart attack

Dietary fat intake affects heart attack risk. Eating foods high in saturated fat (e.g., meat and dairy fat) and trans fatty acids (e.g., margarine, hydrogenated vegetable oils, and many processed foods containing hydrogenated vegetable oils) is directly associated with many nonfatal heart attacks and deaths from coronary heart disease. Consuming foods high in monounsaturated and polyunsaturated fats, as found in nuts and most vegetable oils, is linked to a decreased risk.

High cholesterol

Research consistently shows that people who frequently eat nuts have a dramatically reduced risk of heart disease at least in part because nut consumption lowers cholesterol levels. Of nuts commonly consumed, almonds and walnuts may be most effective at lowering cholesterol. Macadamia nuts have been less beneficial in most studies. Nevertheless, some studies have found a cholesterol-lowering effect from macadamia nuts. Hazelnuts and pistachio nuts have also been reported to help lower cholesterol.

Nuts contain many factors that could be responsible for protection against heart disease, including fiber, vitamin E, alpha-linolenic acid (found primarily in walnuts), oleic acid, magnesium, potassium, and arginine. Therefore, exactly how nuts lower cholesterol or lower the risk of heart disease remains somewhat unclear. Some doctors even believe that nuts may not be directly protective; rather, people busy eating nuts will not simultaneously be eating eggs, dairy, or trans fatty acids from margarine and processed food, the avoidance of which would reduce cholesterol levels and the risk of heart disease. Nonetheless, the remarkable consistency of research outcomes strongly suggests that nuts do help protect against heart disease. Although nuts are loaded with calories, a preliminary trial surprisingly reported that adding hundreds of calories per day from nuts for six months did not increase body weight in humans—an outcome supported by other reports. Even when increasing nut consumption has led to weight gain, the amount of added weight has been remarkably less than would be expected given the number of calories added to the diet.

Hives

Allergy to foods and food additives is a common cause of hives, especially in chronic cases. Nuts are among the foods reported to trigger hives most often. Many other foods and food additives can also cause hives. People with hives should investigate the possibility that food allergies are causing their problem by consulting with a doctor.

Kidney stones

Increasing dietary oxalate can lead to an increase in urinary oxalate excretion. Increased urinary oxalate increases the risk of stone formation. As a result, most doctors agree that kidney stone formers should reduce their intake of oxalate from food as a way to reduce urinary oxalate. Nuts—particularly almonds and peanuts—are among the foods that significantly increase urinary oxalate levels.

Phenylketonuria (PKU)

A PKU diet is low in protein, providing no more than the minimum amount of phenylalanine needed by the body. All high-protein foods, including nuts, are usually eliminated. This diet is supplemented with an amino acid formula to increase protein intake without adding more phenylalanine than is nutritionally required.

Weight loss and obesity

Societies in which people eat less fat tend to have lower rates of obesity. A low fat diet is, however, no guarantee of normal body weight. Sixty percent of the South African population is overweight, despite a comparatively low fat intake (about 22% of calories from fat). Foods with a high proportion of calories from fat should be eliminated from the diet or limited. Nuts should be consumed in moderation, although they are generally healthful for people without weight problems, and may be protective against heart disease.

Wilson’s disease

Wilson’s disease is a genetic disorder that results in excessive accumulation of copper in many parts of the body, particularly the liver. This condition is readily treatable, but if Wilson’s disease is left untreated, it can be fatal.

Most foods contain at least some copper, so it is not possible to avoid the mineral completely. Nuts are relatively high in copper but are quite nutritious. People with Wilson’s disease should eat them in moderation.