Most of us hope that we’ll only have to lose one set of teeth during our lifetime, but for most animals, replacing their teeth is just another fact of life. These so-called polyphyodont animals have
Humans differ by opinions, traits, and baseball team preferences. But one constant factor unifies all humans–we excrete feces, and scientists have recognized that number 2 is number 1 in terms of material for ancient population studies. Humans expel hundreds of … Continue reading
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For many of us, moving to a new house means recruiting a couple good friends to help pack and haul boxes. After a day or two of work, everyone shares a pizza while resting tired muscles at the new home. But 3000 years ago, enjoying a post-move meal may have required a little more planning. Early settlers of remote tropical islands in the Pacific had to bring along all resources needed for survival, including food, from their original homes overseas.
The Lapita people were early settlers of islands in the Pacific, called Remote Oceania (pictured below). When these people, whose culture and biology links to Southeast Asian islands, first decided to sail to the island Vanuatu, they brought domestic plants and animals—or what you might call a ‘transported landscape’—that allowed them to settle this previously uninhabited, less biodiverse (and less resource-available) area. However, the extent to which these settlers and their domestic animals relied on the transported landscape at Vanuatu during the initial settlement period, as opposed to relying on the native flora and fauna, remains uncertain.
To better understand the diet and lives of the Lapita people on Vanuatu, archaeologist authors of a study in PLOS ONE analyzed the stable carbon, nitrogen, and sulfur isotopes from the bones of ~ 50 adults excavated from the Lapita cemetery on Efate Island, Vanuatu.
Why look at isotopes in human remains? Depending on what we eat, we consume varying amounts of different elements, and these are ultimately deposited in our bones in ratios that can provide a sort of “dietary signature”; in this way, the authors can investigate the types of plants, animals, and fish that these early people ate.
For instance, plants incorporate nitrogen into their tissue as part of their life cycle, and as animals eat plants and other animals, nitrogen isotopes accumulate. The presence of these different ratios of elements may indicate whether a human or animal ate plants, animals, or both. Carbon ratios for instance differ between land and water organisms, and sulfur ratios also vary depending on whether they derive from water or land, where water organisms generally have higher sulfur values in comparison to land organisms.
Scientists used the information gained about the isotopes and compared it to a comprehensive analysis of stable isotopes from the settlers’ potential food sources, including modern and ancient plants and animals. They found that early Lapita inhabitants of Vanuatu may have foraged for food rather than relying on horticulture during the early stages of colonization. They likely grew and consumed food from the ‘transported landscape’ in the new soil, but appear to have relied more heavily on a mixture of reef fish, marine turtles, fruit bats, and domestic land animals.
The authors indicate that the dietary analysis may also provide insight into the culture of these settlers. For one, males displayed significantly higher nitrogen levels compared to females, which indicates greater access to meat. This difference in food distribution may support the premise that Lapita societies were ranked in some way, or may suggest dietary differences associated with labor specialization. Additionally, the scientists analyzed the isotopes in ancient pig and chicken bones and found that carbon levels in the settlers’ domestic animals imply a diet of primarily plants; however, their nitrogen levels indicate that they may have roamed outside of kept pastures, eating foods such as insects or human fecal matter. This may have allowed the Lapita to allocate limited food resources to humans, rather than domestic animals.
Thousands of years later, the adage, “you are what you eat” or rather, “you were what you ate” still applies. As the Lapita people have shown us, whether we forage for food, grow all our vegetables, or order takeout more than we would like to admit, our bones may reveal clues about our individual lives and collective societies long after we are gone.
Citation: Kinaston R, Buckley H, Valentin F, Bedford S, Spriggs M, et al. (2014) Lapita Diet in Remote Oceania: New Stable Isotope Evidence from the 3000-Year-Old Teouma Site, Efate Island, Vanuatu. PLoS ONE 9(3): e90376. doi:10.1371/journal.pone.0090376
Image 1: Efate, Vanuatu by Phillip Capper
Image 2: Figure 1
Eat too many carrots and your skin might turn orange, thanks to a group of pigments called carotenoids. Orange skin may not look intimidating to you, but to wild Andean condors, that flash of color in their competitors’ eyes and skin may help them dominate at dinnertime.
Andean condors rely largely on a diet of decaying flesh, but a recent PLOS ONE study suggests that these birds also eat the fresh and partially digested vegetable material in the intestines of carcasses. Condors eat in groups with a strict pecking order, where adult males rank the highest and juvenile females the lowest. Feeding frenzies often lead to conflicts over meals, and this is when the reds, oranges, and yellows of carotenoid pigments may help a young bird signal its dominance in the group. The bare skin of a young condor can turn from pale pink, yellow or dull grey to a vibrant red, orange, or yellow in seconds during these displays.
The researchers investigated how Andean condors and American black vultures acquire these pigments through diet, and what potential biological and environmental factors contribute to the pigments’ biological absorption. They compared pigment concentrations in blood samples from wild condors, black vultures, and captive condors, the latter fed a diet strictly of mammal flesh. The researchers found that captive condors generally had low levels of carotenoids compared to the wild birds, and that the wild condors in particular had a carotenoid concentration about three times higher than that of the wild American black vultures, despite their similar diets. In addition, the wild condors had a high percentage of vegetal matter in their droppings.
These results indicate that wild condors feeding on entire carcasses, including semi-digested vegetal matter, are better able to access the pigments needed for their fast-changing, colorful displays of dominance during a feeding frenzy than the captive condors.
While this research may not inspire us to eat carrots so we turn a dominating shade of orange, it may provide a pivotal foundation for understanding the role carotenoids play in the endangered Andean condors’ diet.
Citation: Blanco G, Hornero-Méndez D, Lambertucci SA, Bautista LM, Wiemeyer G, et al. (2013) Need and Seek for Dietary Micronutrients: Endogenous Regulation, External Signalling and Food Sources of Carotenoids in New World Vultures. PLoS ONE 8(6): e65562. Do i:10.1371/journal.pone.0065562
June is Men’s Health Month! This is a time to bring awareness to preventable health issues and encourage early detection of diseases affecting men. As we wind down from celebrating Father’s Day this past weekend, here are a few articles focusing on some important men’s health issues.
Lowering salt intake helps alleviate a number of health concerns, such as decreasing the risk of heart disease, stroke and stomach cancer. However, how easy is it to reduce your sodium intake without compromising taste, or your wallet? In a recent study, researchers sought to determine how feasible a low-sodium, inexpensive and nutritious meal for men could be. The authors used cost and nutritional data to model and optimize familiar diets. In this analysis, they showed that it is possible to decrease sodium levels to well below the recommended maximum, proving that nutrition does not need to be compromised when preparing an enjoyable low-cost meal.
So what should men be consuming to help with disease prevention? Olive plant leaves (Olea europaea L.) have been used in traditional medicine to treat diabetes for centuries. In a PLOS ONE clinical trial published this year, researchers investigated the effects of olive polyphenols on insulin balance. In this study, 46 male participants received either capsules of olive leaf extract or a placebo for 12 weeks. Through their observations, the researchers found that olive leaf extract significantly improved two factors related to Type 2 Diabetes (insulin sensitivity and pancreatic ?-cell secretory capacity) in overweight, middle-aged men.
What about prostate health, you might ask? The Prostate Specific Antigen test, along with digital rectal examination is widely used for prostate cancer screening. PSA, which stands for Prostate Specific Antigen, is a glycoprotein secreted by epithelial cells of the prostate gland, and individuals with prostate cancer have a higher than normal amount of this compound in their systems. PSA levels can also change in response to external factors like surgery, though, so understanding these other forces is crucial for the test to be effective. In a recent study, authors investigated whether bike riding affects PSA concentration in men. The researchers took blood samples from 129 male participants 60 minutes before a bike ride and 5 minutes after completion. They found that cycling caused their PSA to increase an average of 9.5% when measured within 5 minutes after completing the ride. Based on these findings, the authors suggest a 24–48 hour period of abstinence from cycling before a PSA test to avoid any false positive results.
These articles are just a taste of the published articles touching on men’s health; for more research visit PLOS ONE here.
Wilson N, Nghiem N, Foster RH (2013) The Feasibility of Achieving Low-Sodium Intake in Diets That Are Also Nutritious, Low-Cost, and Have Familiar Meal Components. PLoS ONE 8(3): e58539. doi:10.1371/journal.pone.0058539
de Bock M, Derraik JGB, Brennan CM, Biggs JB, Morgan PE, et al. (2013) Olive (Olea europaea L.) Leaf Polyphenols Improve Insulin Sensitivity in Middle-Aged Overweight Men: A Randomized, Placebo-Controlled, Crossover Trial. PLoS ONE 8(3): e57622. doi:10.1371/journal.pone.0057622
Mejak SL, Bayliss J, Hanks SD (2013) Long Distance Bicycle Riding Causes Prostate-Specific Antigen to Increase in Men Aged 50 Years and Over. PLoS ONE 8(2): e56030. doi:10.1371/journal.pone.0056030
Image Credit: on Flickr by Lindz Graham