Polyamines (putrescine, spermidine, and spermine) are a family of molecules that derive from ornithine through a decarboxylation process. They are essential for cell growth and proliferation, stabilization of negative charges of DNA, RNA transcription, translation, and apoptosis. Recently, it has been demonstrated that exogenously administered spermidine promotes longevity in yeasts, flies, worms, and human cultured immune cells. Here, using a cross-sectional observational study, we determined whole-blood polyamines levels from 78 sex-matched unrelated individuals divided into three age groups: Group 1 (31–56 years, n =26, mean age 44.6±6.07), group 2 (60–80 years, n =26, mean age 68.7±6.07), and group 3 (90–106 years, n =26, mean age 96.5±4.59). The total content of polyamines is significantly lower in groups 2 and 3 compared to group 1 ( p =3.6×10 ⁻¹² ). Interestingly, this reduction is mainly attributable to the lower putrescine content. Group 2 displays the lowest levels of spermidine and spermine. On the other hand, nona/centenarians (group 3) display a significantly higher median relative percentage content of spermine with respect to total polyamines, compared to the other groups (13.2% vs. 14.1% vs. 30.6%, p =6.0×10 ⁻⁴ ). For the first time, we report profiles of polyamines from the whole blood of healthy nona/centenarians, and our results confirm and extend previous findings on the role of polyamines in determining human longevity. However, although we found an important correlation between polyamines levels and age groups, further studies are warranted to fully understand the role of polyamines in determining life span. Also, longitudinal and nutritional studies might suggest potential therapeutic approaches to sustain healthy aging and to increase human life span.

Background: Vitamin D and calcium are important dietary compounds that affect bone mass, even if other minerals (potassium, zinc, etc.) and vitamins (A, C and K) are also involved. Vitamin D and certain minerals, in fact, play an important role in calcium homeostasis and calcium absorption. Hip fracture incidence is higher in Europe and the United States, where calcium is frequently included in the human diet; while the occurrence of these fractures is lower in developing countries, where diets are often poor in calcium. This condition is named the “calcium paradox”, and may be partially explained by phosphate toxicity, which can negatively affect mineral metabolism. It is important to maintain correct dietary calcium-phosphate balance in order to have a healthy life, reducing the risk of osteoporotic fractures in older people. Vitamin D can also act as a hormone; vitamin D2 (ergocalciferol) is derived from the UV-B radiation of ergosterol, the natural vitamin D precursor detected in plants, fungi, and invertebrates. Vitamin D3 (cholecalciferol) is synthesized by sunlight exposure from 7-dehydrocholesterol, a precursor of cholesterol that can also act as provitamin D3. Dietary intake of vitamin D3 is essential when the skin is exposed for short periods to ultraviolet B light (UV-B), a category of invisible light rays such as UV-A and UV-C. This can be considered the usual situation in northern latitudes during the winter season, or the typical lifestyle for older people and/or for people with very white delicate skin. The actual recommended daily intake of dietary vitamin D is strictly correlated with age, ranging from 5 μg for infants, children, teenagers, and adults—including pregnant and lactating women—to 15 μg for people over 65 years.

Donkey milk could be considered a good and safer alternative, compared to other types of milk, for infants affected by cow’s milk protein allergy, when breastfeeding is not possible. Interestingly, donkey milk has low allergenicity, mainly due to the low total casein amount, and the content of some whey proteins that act as bioactive peptides. The amount of lysozyme, an antibacterial agent, is 1.0 g/L, similar to human milk. Lactoferrin content is 0.08 g/L, with this protein being involved in the regulation of iron homoeostasis, anti-microbial and anti-viral functions, and protection against cancer development. Lactoperoxidase, another protein with antibacterial function, is present in donkey milk, but in very low quantities (0.11 mg/L). β-lactoglobulin content in donkey milk is 3.75 g/L—this protein is able to bind and transport several hydrophobic molecules. Donkey milk’s α-lactalbumin concentration is 1.8 g/L, very close to that of human milk. α-lactalbumin shows antiviral, antitumor, and anti-stress properties. Therefore, donkey milk can be considered as a set of nutraceuticals properties and a beverage suitable, not only for the growing infants, but for all ages, especially for convalescents and for the elderly.