High Prevalence of Nickel Allergy in an Overweight Female Population: A Pilot Observational Analysis

PLoS One. 2015 Mar 30;10(3):e0123265. doi: 10.1371/journal.pone.0123265.


Elena Angela Lusi,  Vincenzo Maria Di Ciommo,  Tommaso Patrissi,  Paolo Guarascio



CONTEXT: In our Allergy Unit, we incidentally observed that a low Nickel diet, prescribed for delayed allergy to Nickel sulfate, reduced body mass index (BMI) and waist circumference in overweight patients

OBJECTIVES: This pilot cross-sectional analysis was undertaken to compare the prevalence of Nickel allergy of overweight individuals versus the general population. We also had the chance to report the efficacy of a low Nickel diet on BMI and waist circumference in Nickel-sensitive overweight subjects.

METHODS: Eighty-seven overweight subjects, with a BMI >26 Kg/m2, were consecutively enrolled in a health prevention program, and screened for the presence of Nickel allergy. The enrolled population was mostly females (72/87) (82.8%).

Forty-three overweight women and two men showed a Nickel allergy and started a low Nickel diet. After 6-months of dieting, 24 overweight allergic women could be traced and changes in BMI and waist circumference were calculated.

MAIN OUTCOME MEASUREMENTS: Prevalence of Nickel allergy in overweight.

RESULTS: Prevalence of Nickel allergy in overweight female was 59.7%, compared with a prevalence rate of 12.5% in the general population. A significant reduction in BMI was observed in 24 out of 43 overweight females with Nickel allergy after 24 weeks of a low Nickel diet. Relative to baseline, mean BMI decrease was 4.2±0.5 (P <0.001) and the mean decline in waist circumference was 11.7±0.6 cm (P< 0.001).

CONCLUSIONS: This pilot observational analysis showed a substantially higher prevalence of Nickel allergy among overweight females, especially those with metabolic syndrome and fatty liver disease. A normocaloric low Nickel diet was effective in reducing BMI in this population. Further research is strongly needed to confirm these preliminary findings.

PMID: 25822975



In our Allergy Unit we incidentally observed that a low Nickel diet prescribed for allergy to Nickel sulfate reduced body mass index (BMI) in some overweight patients. Our pilot cross-sectional analysis evaluated 87 obese (BMI>26kg/m2) patients (82F/15M), enrolled in a preventive health program, for the prevalence of Nickel allergy and unexpectedly found 59.7% (43) of the women with Nickel allergy versus the 12.5% rate in the general population and 2/15 (13.3%) men in the study. 100% of the 24 women that completed a six-month low Nickel diet attained a significant decrease (4.2±0.5 (P <0.001)) in BMI relative to baseline, and a mean decline in waist circumference of 11.7±0.6 cm (P< 0.001).

Figure1. Prevalence of Nickel Allergy in the general population and in overweight subjects



Obesity and hypertension, that once plagued only wealthy western countries, have now spread across the globe. Between 1980 and 2008, obesity has doubled worldwide and the number of people with uncontrolled hypertension has increased from 600 million in 1980 to nearly 1 billion in 2008. Changes in diet and sedentary behaviour have contributed to the worldwide increase in obesity, but it remains unclear which policies would effectively reduce obesity. It is accepted that a diet rich in vegetables and fruits is useful in older adults at high risk for heart disease and metabolic disturbances. However, this type of diet for its high nickel content, can be dangerous if consumed by people with a sensitivity to Nickel. The majority of overweight people, especially women of menopausal age, have a nickel allergy. We found an unusually high prevalence of nickel allergy in women and men who were overweight or obese compared with the general population. In particular, the prevalence of Nickel allergy in overweight female was 59.7%, compared with a prevalence rate of 12.5% in the general population (Figure 1).

When a normocaloric diet, formulated to be low only in nickel (79 µg/daily), was prescribed to allergic overweight patients, they manifested a dramatic reduction in body mass index and waist circumference in the first 3 months of diet and normalize some metabolic parameters ( Figure 2) .


Figure 2. Effect of the low nickel diet on BMI, percent body fat, and waist circumference over 3 months in in overweight patients with nickel allergy.


This study demonstrates a higher prevalence of nickel allergy in overweight subjects and theorize a connection between dietary nickel and overweight. Nickel, a trace element found in water, soil and foods, is the most common cause of eczema 1 . Major dietary source of nickel is plant food 2. Plant tissues contain more nickel than animal tissues. Foods that contain high levels of nickel exacerbate the skin dermatitis but also lead to overweight and metabolic disturbances. Nickel causes insulin overload and hyperglycaemia 3-5. During menopause, high dietary nickel and declining estrogen level aggravates the levels of inflammation in women with nickel allergies, increasing the production of IL-17, an inflammatory protein associated with obesity 6-7. High concentrations of nickel could also select and facilitate the growth of Nickel-specific bacteria that trigger an inflammation process in the gut of obese people 8. Nickel is also a cofactor in several enzyme complexes and it seems like that cellular biochemical pathways might provide a mechanism in addition to the gut microflora in promoting metabolic abnormalities. Patch testing for metals in diabetes and nutrition centres might be suggested.



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Elena Angela Lusi M.D.; Ph.D.

St Vincent Private Hospital



e-mail : elenaagelalusi@yahoo.it