From skin health to children’s health, this week’s Nutrition News covers a range of recently published nutritional studies that offer insights into how our bodies function, enabling us to make better decisions about what we eat and drink and how it might impact our health.
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Study illustrates krill oil’s effect on skin health
Krill oil, a rich source of omega-3 fatty acids in phospholipid form, may support skin health by improving skin barrier function according to a recently published study aimed to examine the impact of two different doses of krill oil on skin transepidermal water loss (TEWL) in healthy adults.
The study was reported in the Wiley Online Library and included two randomised, double-blind, placebo-controlled pilot studies, which were conducted with participants who had a baseline TEWL between 10 and 24.9 g/m2/h. In the first study, 51 participants took 1 g of krill oil or a placebo daily, while in the second study, 50 participants consumed 2 g of krill oil or a placebo daily. Outcomes were assessed at the start of the study and again at 6 and 12 weeks.
Both krill oil groups demonstrated significant increases in their omega-3 index compared to the placebo groups. Additionally, those taking krill oil showed notable reductions in TEWL (from 14.47 ± 3.65 to 13.83 ± 3.78 in study 1 and from 14.25 ± 3.21 to 13.02 ± 2.76 in study 2), as well as improved skin hydration and elasticity. The improvements in TEWL, hydration, and elasticity were found to correlate significantly with changes in the omega-3 index.
These findings suggest that daily supplementation with 1 or 2 g of krill oil can support the skin’s ability to retain moisture, which is essential for protecting against external irritants, supporting cell turnover, and maintaining a youthful appearance. Given its safety, low cost, and ease of use, krill oil appears to be a promising dietary addition for those looking to improve skin barrier function and overall skin health. Future research using advanced analytical methods could further elucidate the mechanisms through which krill oil supports skin health.
How long it takes for vitamin C to impact mood
A recent study, as reported in the article “New Study Looks at How Long it Takes for Vitamin C to Work Its Magic on Mood” analysed smartphone survey data to explore changes in mood following vitamin C or kiwifruit intervention in adults with low vitamin C levels. The research is a follow-up to the KiwiC for Vitality study published in 2020, examining secondary outcomes using smartphone-based mood surveys conducted every second day over an eight-week period.
Dr. Tamlin Conner, a psychology researcher at the University of Otago and Associate Editor of Emotion, led the study. Conner highlighted the innovative use of smartphone surveys in nutrition research, which provided insights into thetimeline of mood changes. The brain, which holds a higher concentration of vitamin C than other parts of the body, relies on this nutrient for optimal functioning and previous studies have shown that vitamin C positively impacts cognitive and mental health.
The findings of this study revealed that mood improvements occurred as early as four days into the trial for participants consuming kiwifruit. These positive mood changes, however, dissipated just as quickly during the two-week washout period when participants stopped eating kiwifruit. According to Conner, “Vitamin C is processed quickly in the body, and we think mood improvements corresponded to when participants’ blood vitamin C levels reached saturation.”
The results suggest that whole-food sources, such as kiwifruit, can effectively improve mood in individuals with low vitamin C levels. For those with significant deficiencies, supplementation with vitamin C may help accelerate the restoration of optimal vitamin levels and associated mood benefits. This study underscores the critical role of vitamin C not only in physical health but also in supporting mental well-being. Further research is needed to expand on these findings, exploring how dietary interventions can be strategically used to support mood and cognitive function.
Vitamin D supplementation analysed in preterm babies
Vitamin D deficiency is prevalent among extremely preterm (EP) infants, with most having serum 25-hydroxyvitamin D levels below 20 ng/mL at birth. However, the optimal vitamin D supplementation practices for EP infants remain unclear. A study reported in the article “Survey of vitamin D supplementation practices in extremely preterm infants” aimed to assess the current vitamin D supplementation strategies in U.S. neonatal intensive care units (NICUs) to provide a foundation for future clinical trials.
An online survey was conducted to evaluate vitamin D intake and supplementation practices across NICUs in the United States caring for EP infants. The survey collected responses from 253 NICUs, representing the majority of academic and level IV centres. The results showed that nearly all centres (97%) provided enteral vitamin D supplementation during the NICU stay, with 400 IU/day being the most commonly used dosage (77%). More than half of the NICUs (56%) based the initiation of supplementation on feeding volume, with 71% starting supplementation once infants achieved at least 120 ml/kg/day. Furthermore, 94% of NICUs prescribed vitamin D supplementation upon discharge.
These findings highlight the widespread use of a 400 IU/day dosage for vitamin D supplementation in EP infants across U.S. NICUs. However, recent research suggests that early, high-dose vitamin D supplementation (800 IU/day) may offer additional benefits, such as reducing the risk of bronchopulmonary dysplasia, infections, and long-term disabilities in EP infants.
The survey results indicate a variation in vitamin D supplementation practices, with different timings and doses used across centres. This underscores the need for clinical trials comparing the standard 400 IU/day regimen with earlier and higher doses to determine the most effective strategies for improving clinical outcomes and establishing optimal vitamin D levels in EP infants. Further research will be crucial to guide best practices for vitamin D supplementation in children’s health.
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Alison is the Founder of Metabolics who writes about Metabolics updates, events and natural healthcare. Her experience and passion for natural supplements and healthcare comes from her years of experience as a practising osteopath, having founded Metabolics in her search for high quality, natural products in her own work. Alison has been a qualified and practising Osteopath since 1981 and regularly gives seminars on a range of healthcare subjects to the wider practitioner community helping share her knowledge and experience.