It is hypothesized that for people with dandruff, skin cells may mature and be shed in 2–7 days, as opposed to around a month in people without dandruff. The result is that dead skin cells are shed in large, oily clumps, which appear as white or grayish flakes on the scalp, skin and clothes. According to one study, dandruff has been shown to be possibly the result of three factors:
Skin oil, commonly referred to as sebum or sebaceous secretions
The metabolic by-products of skin micro-organisms (most specifically Malassezia yeasts)
Individual susceptibility and allergy sensitivity. Microorganisms
Older literature cites the fungus Malassezia furfur (previously known as Pityrosporum ovale) as the cause of dandruff. While this species does occur naturally on the skin surface of people both with and without dandruff, in 2007, it was discovered that the responsible agent is a scalp specific fungus, Malassezia globosa, that metabolizes triglycerides present in sebum by the expression of lipase, resulting in a lipid byproduct: oleic acid. During dandruff, the levels of Malassezia increase by 1.5 to 2 times its normal level. Oleic acid penetrates the top layer of the epidermis, the stratum corneum, and evokes an inflammatory response in susceptible people which disturbs homeostasis and results in erratic cleavage of stratum corneum cells. Seborrhoeic dermatitis
In seborrhoeic dermatitis, redness and itching frequently occur around the folds of the nose and eyebrow areas, not just the scalp. Dry, thick, well-defined lesions consisting of large, silvery scales may be traced to the less common condition of scalp psoriasis.
Nutrition
There is currently limited evidence to form a strong conclusion to recommend the use of any form of carbohydrate in preventing or reducing cognitive decline in older adults with normal cognition or mild cognitive impairment. So, more large and higher quality evidence is needed to evaluate memory improvement and find nutritional issues due to carbohydrates. Outlook
MCI does not usually interfere with daily life, but around 50 percent of people diagnosed with it go on to develop Alzheimers disease within five years (mainly for people diagnosed with memory impairments). This diagnosis can also serve as an early indicator for other types of dementia, although MCI may remain stable or even remit. Prevalence
The prevalence of MCI varies by age. The prevalence of MCI among different age groups is as follows: 6.7% for ages 60–64; 8.4% for ages 65–69, 10.1% for ages 70–74, 14.8% for ages 75–79, and 25.2% for ages 80–84. After a two-year follow-up, the cumulative incidence of dementia among individuals who are over 65 years old and were diagnosed with MCI was found to be 14.9%.Globally, approximately 16% of the population over the age of 70 experiences some type of mild cognitive impairment. See also

Menopause-related cognitive impairment – similar symptoms, appears shortly after menopause, and can be treated with hormone replacement therapy


== References ==