Fish oil effects on tissular fatty acids and plasma lipid peroxidation in zinc deficient rats

Rats allowed to self-select zinc-deficient lard and fish-oil diets did not develop a preference for fish-oil diet

Zinc (Zn)-deficiency causes a reduction in food intake and alters adipose metabolism. The effect of zinc restriction in rats on the selection of fish-oil and lard was studied during a period of reduced appetite. The reduction of appetite was caused by an experimentally induced Zn-deficiency. Four-week-old male rats were divided into three dietary treatment groups: Zn-adequate (ZnA, 30.9 mg Zn/kg), marginal Zn-deficient (ZnM, 5.9 mg Zn/kg) or Zn-deficient (ZnD, 0.9 mg Zn/kg). The three groups were placed on a self-selection regimen of the ZnA-fish-oil diet (ZnA-FD) and the ZnA-lard diet (ZnA-LD), the ZnM-FD and the ZnM-LD or the ZnD-FD and the ZnD-LD, respectively for 24 d. The amount of the FD intake in the ZnD group decreased to 0.5 g/d after day 4-6 of self-selecting on the LD and the FD and no significant increase in the FD intake in the group was observed during the self-selection period. However, after day 7-9 and 13-15, the FD intake of the ZnA and the ZnM groups increased, respectively, and at the end of the self-selection period the ZnM and the ZnA rats consumed about 2.0 g FD/d and 4.5 g FD/d, respectively. The FD intake ratio [FD intake (g)/total intake (g)] in the ZnD rats during the self-selection period was the lowest and that in the ZnA rats was the highest of three groups. In conclusion, we showed that zinc status alters fish-oil and lard selection patterns and ZnD rats did not show a preference for fish-oil.

Double-blind, placebo-controlled study of zinc sulfate in the treatment of attention deficit hyperactivity disorder

BACKGROUND

The most commonly used medications for attention deficit hyperactivity disorder (ADHD) are the psychostimulants. There is, however, considerable awareness in alternative, nonstimulant therapies, because some patients respond poorly to stimulants or are unable to tolerate them. Some studies suggest that deficiency of zinc play a substantial role in the aetiopathogenesis of ADHD. Therefore, to assess the efficacy of zinc sulfate we conducted treatment trial.

METHODS

Patients with a primary DSM-IV diagnosis of ADHD (N=400; 72 girls, 328 boys, mean age=9.61+/-1.7) were randomly assigned in a 1:1 ratio to 12 weeks of double-blind treatment with zinc sulfate (n=202) (150 mg/day) or placebo (n=198). Efficacy was assessed with the Attention Deficit Hyperactivity Disorder Scale (ADHDS), Conners Teacher Questionnaire, and DuPaul Parent Ratings of ADHD. Primary efficacy variables were differences from baseline to endpoint (last observation carried forward) in mean ADHDS and Conners Teacher Questionnaire scores between the zinc sulfate and the placebo groups. Safety evaluations included monitoring of adverse events, vital signs and clinical laboratory values.

RESULTS

Zinc sulfate was statistically superior to placebo in reducing both hyperactive, impulsive and impaired socialization symptoms, but not in reducing attention deficiency symptoms, as assessed by ADHDS. However, full therapeutic response rates of the zinc and placebo groups remained 28.7% and 20%, respectively. It was determined that the hyperactivity, impulsivity and socialization scores displayed significant decrease in patients of older age and high BMI score with low zinc and free fatty acids (FFA) levels. Zinc sulfate was well tolerated and associated with a low rate of side effect.

CONCLUSIONS

Zinc monotherapy was significantly superior to placebo in reducing symptoms of hyperactivity, impulsivity and impaired socialization in patients with ADHD. Although by themselves, these findings may not be sufficient, it may well be considered that zinc treatment appears to be an efficacious treatment for ADHD patients having older age and high BMI score with low zinc and FFA levels.