Vitamin D is essential to a healthy skeleton because it helps the bones absorb calcium in order to maintain their strength. It is also essential to the nerve cells, muscles and immune system, according to the Office of Dietary Supplements, a division of the National Institutes of Health. While the body can produce vitamin D after the bare skin is exposed to sunlight, there are few dietary sources of the nutrient, including dairy, fortified orange juice, some fish and eggs.

According to the United States Department of Agriculture, one large whole egg contains 41 International Units (IUs) of vitamin D, which can provide about 7 percent of the Recommended Daily Allowance for individuals aged 1 to 70 years of age. For people who may be concerned about heart health, measurements now show that eggs contain 14 percent less cholesterol than previously recorded, according to the American Egg Board (AEB).

"Eggs can be paired with almost any vegetable, making it easy for Americans to follow the Dietary Guidelines for Americans 2010 and MyPlate recommendation to 'make half your plate fruits and vegetables,'" said Helenbeth Reynolds, MPH, RD, of the AEB.

Researchers from Spain investigated the health benefits of nuts based on their content of polyunsaturated fats, which can help remove cholesterol from blood vessels, and polyphenols, a class of antioxidants that may promote healthy aging. For their experiment, the scientists selected 42 individuals who had poor metabolism, which could have negative effects on the heart, blood sugar, blood pressure and weight. A group of 22 subjects were instructed to eat one ounce of mixed nuts – including walnuts, almonds and hazelnuts – every day for 12 weeks. The rest of the participants were told to avoid the food.

Results showed that the individuals who ate nuts had higher levels of serotonin in their body, which had positive effects on their heart health, mood and feelings of hunger, as published in the Journal of Proteome Research.

Nuts are rich in a myriad of nutrients, according to the National Institutes of Health. These include vitamin E and minerals such as selenium, magnesium, copper and potassium. Furthermore, they contain omega-3 fatty acids, which a growing body of research suggests can benefit the heart and other systems of the body.

The researchers thought that proanthocyanidins (PACs), a group of flavonoids found in cranberries, were responsible for maintaining healthy excretory cells. Their new study focused on colonies of the bacterium E. coli. Certain strains of this pathogen are covered with hair-like projections that help them form a biofilm and latch onto human cells, which leads to negative effects.

Based on previous research on cranberries, the WPI team grew two groups of E. coli in their lab: one was incubated in the presence of PACs, while the other was treated with commercially available cranberry juice cocktail. Results showed that colonies grown with the juice were less likely to be able to form the biofilm needed to attach to human cells, as published Oct. 31 in Food Science and Biotechnology.

The National Center for Complementary and Alternative Medicine, a division of the National Institutes of Health (NIH), is currently conducting studies to assess the health benefits of cranberries. Other NIH agencies are looking at how cranberries may affect the aging process.

In the gut and skin there are white blood cells known as intra-epithelial lymphocytes (IELs), which help protect the body from the outside world. IELs serve important functions in fighting external pathogens and wound healing, according to researchers from the Babraham Institute in the UK. The population size of IELs depends in part on the presence of a protein on the surfaces of these cells. Previous studies suggested that a compound in cruciferous vegetables influenced the activity of this protein in IELs.

In a laboratory experiment on mice, the scientists fed their subjects a diet lacking in vegetables. Eventually these animals had fewer IELs, making them more susceptible to infections and injury, as published Oct. 13 in the journal Cell.

"I would have expected cells at the surface would play some role in the interaction with the outside world, but such a clear cut interaction with the diet was unexpected," said author Marc Veldhoen. "After feeding otherwise healthy mice a vegetable-poor diet for two to three weeks, I was amazed to see 70 to 80 percent of these protective cells disappear."

Further research is necessary to verify these effects in humans.

Among the many nutrients found in tomatoes are vitamins A and C, as well as other antioxidants such as lycopene and polyphenols, a class of plant chemicals that previous studies have shown to support good cardiovascular and immune health. Researchers in Spain were curious about whether certain farming methods affected the amount of polyphenols that tomatoes contained, and did an experiment to compare organically farmed tomatoes to vegetables from conventional growing methods.

Results showed that tomatoes that were farmed using organic methods had more polyphenols.

"In conventional agriculture, the nitrogen can be added in soluble form, as a fertilizer, whereas in organic production the plant receives no artificial nutrients and therefore responds by activating defense mechanisms that increase the levels of polyphenols," said author Anna Vallverdu-Queralt. "As a result, conventionally grown plants can lose resistance to disease and present lower levels of nutrients, minerals and secondary metabolites."

Part of the research team comes from the University of Barcelona's Natural Antioxidants Group, which also studies grapes, chocolate, beer and other foods.

Jurisdictions in California, New York and South Africa have passed laws banning the inclusion of toys with fast food meals, in an effort to fight increasing trends of childhood obesity. Researchers in Wisconsin and Oregon were curious about the effect that these toys would have on healthier meals, and published their study in the Journal of Public Policy and Marketing.

The experiment asked pre-schoolers how they would feel about different combinations of options: a meal of pizza, fries and soda; a meal of soup, milk and mixed vegetables; an individual toy; a toy part of a collectible series; and having no toy at all.

Results showed that the healthier meal was more desirable when they came with toys. Between two meals offered with no toys, the fast food was more popular. Overall, meals that included collectible toys from a set were the most wanted.

"The study tells us that the inclusion of a collectible toy influences the children's perceptions of how the food is going to taste, and whether they will like it," said researcher T. Bettina Cornwell. Most parents surveyed said they were fine with using toys to market healthier food.

The study concluded that the vegetable ingredients of the cold Spanish soup gazpacho, which include peppers, tomatoes, garlic, onions and cucumbers, lost some of their naturally occurring vitamin C when prepared to make the final dish. It was also discovered that the acidity of certain vegetables decreased, possibly suggesting a loss of antioxidant capacity.

Once the soup was put together from its basic ingredients, levels of vitamin C and organic acids experienced the most significant reductions. As a result, the study's researchers advise those with a taste for gazpacho to eat it immediately after preparation to minimize vitamin and antioxidant loss.

Gazpacho is nonetheless notable for its wide-ranging vitamin, mineral and antioxidant content. Vitamins A, C and E, the minerals phosphorus, iron, calcium, fiber and magnesium as well as lycopene, an antioxidant prominent in tomatoes, can all be found there.

The Mayo Clinic states that vitamin C is necessary to promote a healthy immune system as well as the body's formation of collagen in bones, cartilage, muscle and blood vessels. Levels of this vitamin can be bolstered with vitamin supplements and a diet rich in citrus fruits. 

A recent study published in the journal Pharmacological Research indicated that natural antioxidants may promote good sexual health in both men and women.

The researchers explained that antioxidants may promote overall well-being, thereby enhancing the prospects that individuals will maintain optimal sexual health as they age.

The study's results showed that antioxidants create this effect by helping to balance nitric oxide and oxidative stress in the body.

"Some people and physicians are already using antioxidants to help with fertility problems, but we don’t have the real scientific evidence yet to prove its efficacy. It’s time to change that," said lead researcher Tory Hagen.

According to WebMD, one cup of berries may provide the recommended daily intake of antioxidants.

Now, a recent study published in the journal Pediatrics has shown that supplements of an omega 3 fatty acid called docosahexaenoic acid (DHA) given to pregnant women may promote overall well-being in babies up to six months after birth.

The research involved 1,100 pregnant women who were given 400 mg doses of DHA supplements from 18 weeks gestation until delivery.

The study's results showed that babies of mothers who took the omega 3 supplements had higher levels of respiratory health than infants of women who were given a placebo.

"This is a large scale, robust study that underscores the importance of good nutrition during pregnancy. Our findings indicate that pregnant women taking 400 mg of DHA are more likely to deliver healthier infants," said researcher Usha Ramakrishnan of the Hubert Department of Global Health at Emory's Rollins School of Public Health.

The Mayo Clinic notes that mothers-to-be should also focus on consuming 800 micrograms of folate or folic acid each day throughout pregnancy.

Either way, consuming a plant-based diet may help improve their digestive health, according to a recent study published on the website of the British Medical Journal.

High fiber intake has long been associated with healthy digestive function, and individuals who avoid meat typically consume more products that are rich in the nutrient.

The researchers followed a group of more than 47,000 individuals over the course of nearly 12 years. The study's results showed that those who consumed the most fiber – many of whom were vegetarians – were the least likely to develop bowel problems.

The investigators said that there may be a number of serious health problems that can be averted through dietary changes and healthy lifestyle modifications. However, they noted that "far more evidence is needed before dietary recommendations can be made to the general public."

According to the National Digestive Diseases Information Clearinghouse, as many as 70 million Americans are affected by poor digestive function.