This study showed that most acne patients had serum ALB, GLO, and TP concentrations that were within the normal range. However, serum levels of ALB, GLO, and TP in male and female acne patients were lower than in the control group. We suggest that the requirements for protein of acne patients are higher than those of health people and that acne patients are deficient in protein, even when serum ALB, GLO, and TP levels are above the normal range.
Oxidative damage plays an important role in acne pathogenesis[7]. ALB is the most abundant circulating protein in plasma and has important antioxidant activities[8]. Serum ALB levels have been considered to be one of the best indicators of nutritional status; furthermore, hypoalbuminemia has been thought to indicate protein deficiency[9]. Abnormal liver function can also lead to decreased ALB synthesis, but transaminase levels in patients of this study were within the normal range. Some recent reports have shown that serum ALB is more significantly influenced by factors other than nutritional intake. Inflammation may reduce serum ALB concentrations independently of malnutrition[10]. Macrophages and neutrophils secrete proinflammatory cytokines such as TNF-α, IL-1β, and IL-8, which might affect serum protein production[11]. The molecular weight of albumin is small, and it is easy to leak out from urine. Excessive exercise or micro-pathological changes of the glomerulus and renal tubules may lead to microalbuminuria. Serum ALB levels in acne patients were lower than in the control group (P < 0.05), suggesting that the serum ALB in acne patients was not enough to prevent and inhibited the oxidative damage from acne lesions.
The GLO fraction includes hundreds of serum proteins, including carrier proteins, enzymes, the complement system, and immunoglobulins[12]. Immune GLO contains a broad range of immune antibodies that oppose pathogens and foreign antigens. These antibodies are critical for replacement therapy in patients with humoral immune deficiencies. GLO plays an important role in immunity and inflammation and serves as a carrier of sex hormones[12]. Acne patients with reduced immunoglobulin cannot effectively protect themselves against bacterial infections. The serum GLO levels in male patients with moderate, severe, and mild acne were significantly lower than those in the control group (P < 0.05). The serum GLO levels in all female acne patients were significantly lower than in the control group (P < 0.05).
Serum TP comprises ALB and GLO. The serum ALB concentrations in both male and female mild, moderate, and severe acne groups were not significantly different from the normal control group (P > 0.05). Serum GLO levels of female patients with mild, moderate, and severe acne were not significantly lower than those in the control group (P > 0.05). Conversely, serum TP levels in mild, moderate, and severe male and female acne patients were significantly lower than in the control group (P < 0.01). The severity of female and male patients was negatively correlated with serum ALB, GLO, TP, and PA levels (P < 0.01).
The ALB/GLO ratio (AGR = ALB/(TP -ALB) is the ratio of serum ALB to non-ALB proteins[13]. The AGR of female patients was not significantly higher than that of the normal control group, which is probably due to the lower serum ALB level in female patients, who showed no significant decrease in GLO. The AGR in male acne patients was significantly higher than in the control group (P < 0.01). Serum ALB and GLO levels in acne patients were lower than in healthy people, but GLO was remarkably decreased. Increased AGR indicated decreased immunity of acne patients.
PA, also known as transthyretin, has a half-life in serum of 2–3 days, which is much shorter than that of ALB. PA is therefore more sensitive to changes in protein-energy status than ALB, and its concentration closely reflects recent dietary intake rather than overall nutritional status[14]. However, low serum PA levels may signal not only malnutrition, as it is affected by other factors. Inflammatory stress, metabolic stress, and zinc deficiency downregulate PA, which is synthesized in the liver. Our results showed that serum PA levels in female acne patients were significantly lower than in the control group. Although there was not a significant decrease in serum PA concentration in male patients, serum PA concentrations in male and female patients were inversely correlated to the severity of acne. These results suggested that serum PA levels may affect acne inflammation.
Most of the patients in this study were from low income groups, such as young students, graduate students, and ordinary workers. Some patients were pursuing a weight loss by excessive dieting. Many young acne patients were studying and working hard for entrance examinations, employment, and jobs, and neglecting their nutrition: their diets were deficient in protein. The average age of the acne patients in this study was less than 20, and most were teenagers.
Adolescence is a nutritionally critical period of life. The dramatic increase in physical growth and development puts greater pressure on nutritional requirements, as it is during this period that adolescents experience a weight gain equivalent to 65% of their weight at the beginning of the period (or 40% of their final weight) and a height increase equivalent to 15% of their adult height. The nutritional requirements of adolescents are higher than in any other age group[15]. The severity of female and male acne patients was negatively correlated with serum TP, ALB, GLO, and PA levels (P < 0.01). These results suggested that protein deficiency is an important factor in the pathogenesis of acne. If acne patients have protein malnutrition, it will not only lead to acne relapse and delayed healing, but will also impair the patient’s quality of life and hinder their normal growth and development. However, the correlation coefficient is low (r < 0.75), indicating that the correlation between protein malnutrition and the severity of acne is not conspicuousness or insidious. Acne is a multifactorial disease. There are many pathogenic factors that cause acne, such as vitamin deficiency, insomnia, fatigue, infection and other factors. Protein malnutrition is a hidden and latent pathogenic factor of acne, which is easy to ignore, or misdiagnosed by doctors.
According to the mean and standard deviation of males and females in the normal control group (Table 2), the lower 95% confidence interval reference value of ALB, GLO, TP, and PA in males and females in the control group were evaluated by the formula: (\(\stackrel{-}{\text{X}}\)-1.96 s). The results for male participants were: ALB ≥ 43.69 g/L, GLO ≥ 21.465 g/L, TP ≥ 68.34 g/L, and PA ≥ 175.307 g/L; for female participants the results were: ALB ≥ 43.296 g/L, GLO ≥ 21.47 g/L, TP ≥ 67.84 g/L, and PA ≥ 176.97 g/L. When serum protein ALB, GLO, TP, and PA are lower than these values, it indicates that the patient has increased demand for protein. If the patient continues to diet without adequate protein supplementation, acne lesions will be recurrent and difficult to cure even with systemic drug treatment.
There were limitations to this study. First, some patients may not have protein malnutrition but still show abnormal serum lipid profiles and hyperhomocysteinemia. Due to the limitations of conditions, this study did not make a comprehensive assessment of the nutritional status of patients. Second, the number of patients in this study was small. Third, there is no further research or analysis on the causes of protein malnutrition in these acne patients.
The results of this study showed that the serum protein concentrations of acne patients were significantly lower than healthy controls. We assume that acne patients are in malnutrition and/or that their requirements for protein are higher despite the serum protein concentrations of most of the patients being in the normal range. A low serum protein concentration can be primarily regarded as a signal to identify severe acne patient who require careful assessment and monitoring and for whom nutritional support may be needed as part of the treatment plan. Nutritional assessment and monitoring protocols should be developed for acne patients, and these protocols should include assessments of adequate nutritional intake and possibly serial measurements of serum proteins. A suitable high protein diet and vitamin supplementation (High dose niacin[16], folic acid, and vitamin B12) may benefit all acne patients, even if they are not definitely in malnutrition.