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Providing perspectives on recent research into vitamins and nutritionals


When it Comes to Nutrition, Herding Cats is Easier than Humans

By Michael McBurney

Two interesting vitamin D stories in the news today. In humans, higher vitamin D levels are linked to reduced risk of depression. In animals, low vitamin D status predicts 30 day mortality in hospitalized cats.

Unlike humans who can produce vitamin D cutaneously, cats cannot. Thus cats are 100% dependent upon dietary sources of vitamin D. Titmarsh and colleagues measured serum 25(OH)D concentrations in hospitalized cats, hypothesizing that vitamin D status would predict mortality. Cats with low serum 25(OH)D concentrations (<74 nmol/L) were 8.27 times more likely to die in 30 days of initial assessment than those in the highest tertile (>110 nmol/L). This relationship is consistent with human findings (Zittermann et al, 2012; Ginde et al, 2009; Hutchinson et al, 2010).

Based on data from 5,371 adults (35-70y) living in Finland, Jaaskelainen and colleagues identified 354 diagnosed with depressive disorder and 222 with anxiety disorder. The relative odds between the highest and lowest tertile of serum 25(OH)D concentrations was 0.65 after adjustment for sociodemographic factors. The mean 25(OH)D concentrations for the lowest and highest tertiles were 26.7 and 68.1 nmol/L, respectively. The population mean was 45.6 nmol/L. The authors speculate that vitamin D receptors and activitating enzymes (1α-hydroxylase) in the prefrontal cortex and hippocampus of the brain may be associated with the pathophysiology of depression.

For readers who believe natural, organic foods which have been minimally processed are the healthiest, think again. Few foods are naturally rich in vitamin D.

Cats can live up to 15 years. So can dogs. In dog years, 15 years is 105 human years! Pet owners typically feed processed, often pelleted, products containing the correct balance of vitamins, minerals and energy nutrients (protein, fat and carbohydrates).

For people, it is more difficult. Why? Because we pick and choose from thousands of choices, trying to get the right blend of nutrients, and often failing.

In fact, most domesticated cats, dogs, pigs, chickens, horse, and cows are fed highly processed, canned or pelleted products. These “feeds” are consumed as a complete ready-to-use food (total mixed ration in agricultural parlance) or as a supplement (concentrate) to the other feeds their owners provide.

Because feed companies formulate, i.e. fortify, animal feeds to meet age and sometimes condition (pregnancy, lactation, digestive health, heart health, blood glucose management, etc) requirements, domesticated animals can have long, healthy lifespans (presuming proper weight management of the animal).

Just like domesticated animals, fortified foods help ensure our bodies obtain needed vitamins.

Main Citations

Titmarsh H, Kilpatrick S, Sinclair J, Boag A, Bode EF, Lalor SM, Gaylor D. Vitamin D status predicts 30 day mortality in hospitalized cats. 2015 PLoSONE  doi: 10.1371/journal.pone.0125997

Jaaskelainen T, Knekt P, Suvisaari J, Mannisto S, Partonen T, Saaksjarvi K, Kaartinen NE, Kanerva N, Lindfors O. Higher serum 25-hydroxyvitamin D concentrations are related to a reduced risk of depression. 2015 Br J Nutr  doi: 10.1017/S0007224515000689

Other Citations

Zittermann A, Iodice S, Pilz S, Grant WB, Bagnardi V, Gandini S. Vitamin D deficiency and mortality risk in the general population: a meta-analysis of prospective cohort studies. 2013 Am J Clin Nutr doi:  10.3945/ajcn.111.014779

Ginde AA, Scragg R, Schwartz RS, Camargo CA. Prospective Study of Serum 25-Hydroxyvitamin D Level, Cardiovascular Disease Mortality, and All-Cause Mortality in Older U.S. Adults. 2009 J Am Geriatr Soc  doi: 10.1111/j.1532-5415.2009.02359.x

Hutchinson MS, Grimnes G, Joakimsen RM, Figenschau Y, Jorde R. Low serum 25-hydroxyvitamin D levels are associated with increased all-cause mortality risk in a general population: the Tromsø study. 2010 Eur J Endocrinol doi: 10.1530/eje-09-1041