Phytochemicals In Plants Can Help You Lose Weight, Look Younger, Enhance Immunity
Eating more plant-based foods, which are rich in substances called phytochemicals, seems to prevent oxidative stress in the body, a process associated with obesity and the onset of disease, according to findings published online in advance of the print edition of the Journal of Human Nutrition and Dietetics.
To get enough of these protective phytochemicals, researchers suggest eating plant-based foods such as leafy greens, fruits, vegetables, nuts and legumes at the start of a meal. Using what is known as a phytochemical index, which compares the number of calories consumed from plant-based foods compared with the overall number of daily calories, could also help people make sure they remember to get enough phytochemicals during their regular meals and snacks, said Heather K. Vincent, Ph.D., the lead author of the paper.
“We need to find a way to encourage people to pull back on fat and eat more foods rich in micronutrients and trace minerals from fruits, vegetables, whole grains and soy,” said Vincent, an assistant professor in the UF Orthopaedics and Sports Medicine Institute. “Fill your plate with colorful, low-calorie, varied-texture foods derived from plants first. By slowly eating phytochemical-rich foods such as salads with olive oil or fresh-cut fruits before the actual meal, you will likely reduce the overall portion size, fat content and energy intake. In this way, you’re ensuring that you get the variety of protective, disease-fighting phytochemicals you need and controlling caloric intake.”
The researchers studied a group of 54 young adults, analyzing their dietary patterns over a three-day period, repeating the same measurement eight weeks later. The participants were broken into two groups: normal weight and overweight-obese.
Although the adults in the two groups consumed about the same amount of calories, overweight-obese adults consumed fewer plant-based foods and subsequently fewer protective trace minerals and phytochemicals and more saturated fats. They also had higher levels of oxidative stress and inflammation than their normal-weight peers, Vincent said. These processes are related to the onset of obesity, heart disease, diabetes and joint disease, she added.
“Diets low in plant-based foods affect health over the course of a long period of time,” Vincent said. “This is related to annual weight gain, low levels of inflammation and oxidative stress. Those are the onset processes of disease that debilitate people later in life.”
Oxidative stress occurs when the body produces too many damaging free radicals and lacks enough antioxidants or phytochemicals to counteract them. Because of excess fat tissue and certain enzymes that are more active in overweight people, being obese can actually trigger the production of more free radicals, too.
Because many phytochemicals have antioxidant properties, they can help combat free radicals, Vincent said. Phytochemicals include substances such as allin from garlic, lycopene from tomatoes, isoflavones from soy, beta carotene from orange squashes and anythocyanins from red wine, among others.
“People who are obese need more fruits, vegetables, legumes and wholesome unrefined grains,” she said. “In comparison to a normal-weight person, an obese person is always going to be behind the eight ball because there are so many adverse metabolic processes going on.”
Instead of making drastic changes, people could substitute one or two choices a day with phytochemical-rich foods to make a difference in their diets, Vincent said. For example, substituting a cup of steeped plain tea instead of coffee or reaching for an orange instead of a granola bar could increase a person’s phytochemical intake for the day without even changing the feeling of fullness. Over time, replacing more pre-packaged snacks with fresh produce or low-sugar grains could become a habit that fights obesity and disease, Vincent said.
“We always want to encourage people to go back to the whole sources of food, the nonprocessed foods if we can help it,” Vincent said. “That would be the bottom line for anyone, regardless of age and body size, keep going back to the purer plant-based foods. Remember to eat the good quality food first.”
Currently, there are no recommendations for how much of these plant compounds people should be getting each day, says Susanne Talcott, Ph.D., an assistant professor of food science and nutrition at Texas A&M University. Using the phytochemical index could be a good way to come up with these recommendations, she said.
Like Vincent, Talcott also cautions people to try and stick to the whole sources of foods and be wary of processed foods that promise benefits from added plant compounds.
“Consumers should stick with what we have known for decades and eat fresh or frozen fruits and vegetables,” she said. “Stick with those kinds of foods rather than reaching out for a tropical wonder pill or juice.”
Well-planned vegan diets contain all the nutrients we need to remain strong and healthy. When people go vegan, they often eat more fruit and vegetables, and enjoy meals higher in fiber and lower in saturated fat.
How does your diet compare to The Vegan Plate by Dietitians Brenda Davis and Vesanto Melina? The Vegan Plate shows that sources of calcium are found in many food groups. It draws attention to the importance of beans, lentils, chickpeas, nuts, and seeds in a healthy diet. The Vegan Plate also highlights that it is essential to get enough vitamin B12, vitamin D, omega-3 fat, and iodine. You will notice that there is no mention of high fat, high sugar processed foods. There are many animal-free items that fall into this group, but they are not an essential part of a varied and balanced vegan diet. Limiting your intake of processed food will help you to maximize the quality of your diet.
The tips below will help you to get the most out of your vegan lifestyle:
* Make sure that your diet contains a variety of fruit and vegetables – eat a rainbow! * Choose higher fiber starchy foods, such as oats, sweet potato, wholegrain bread, wholegrain pasta, and brown rice * Include good sources of protein in most meals, such as beans, lentils, chickpeas, tofu, soya alternatives to milk and yogurt, or peanuts * Eat nuts and seeds daily, especially those rich in omega-3 fat * Eat calcium-rich foods daily, such as calcium-fortified products and calcium-set tofu * Ensure that your diet contains a reliable source of vitamin B12 (either fortified foods or a supplement) * Ensure that your diet contains a reliable source of iodine (arguably a supplement is the best option) * Everyone in the should consider a vitamin D supplement during autumn and winter, and year-round supplementation should be considered by people who do not regularly expose their skin to sunlight, and those with darker skin * Use small amounts of spread and oil high in unsaturated fats, such as vegetable (rapeseed) and olive oils * Season food with herbs and spices instead of salt * Drink about six to eight glasses of fluid a day * Consider a supplement containing long-chain omega-3 fats from microalgae, particularly for infants and those who are pregnant or breastfeeding * Check out our information about vitamins B12 and D, calcium, iron, zinc, selenium, and omega-3 fats to make sure that you are getting enough * Keep active * Maintain a healthy weight, or lose some weight if it is above the healthy range
Not only does exercise make most people feel better and perform physical tasks better, it now appears that exercise — specifically, resistance training — actually rejuvenates muscle tissue in healthy senior citizens.
A recent study, co-led by Buck Institute faculty member Simon Melov, PhD, and Mark Tarnopolsky, MD, PhD, of McMaster University Medical Center in Hamilton, Ontario, involved before and after analysis of gene expression profiles in tissue samples taken from 25 healthy older men and women who underwent six months of twice weekly resistance training, compared to a similar analysis of tissue samples taken from younger healthy men and women.
The gene expression profiles involved age-specific mitochondrial function; mitochondria act as the “powerhouse” of cells. Multiple studies have suggested that mitochondrial dysfunction is involved in the loss of muscle mass and functional impairment commonly seen in older people. The study was the first to examine the gene expression profile, or the molecular “fingerprint”, of aging in healthy disease-free humans.
Results showed that in the older adults, there was a decline in mitochondrial function with age. However, exercise resulted in a remarkable reversal of the genetic fingerprint back to levels similar to those seen in the younger adults. The study also measured muscle strength. Before exercise training, the older adults were 59% weaker than the younger adults, but after the training the strength of the older adults improved by about 50%, such that they were only 38% weaker than the young adults.
“We were very surprised by the results of the study,” said Melov. “We expected to see gene expressions that stayed fairly steady in the older adults. The fact that their ‘genetic fingerprints’ so dramatically reversed course gives credence to the value of exercise, not only as a means of improving health, but of reversing the aging process itself, which is an additional incentive to exercise as you get older.”
The study participants were recruited at McMaster University. The younger (20 to 35 with an average age of 26) and older (older than 65 with an average age of 70) adults were matched in terms of diet and exercise; none of them took medication or had diseases that can alter mitochondrial function. Tissue samples were taken from the thigh muscle. The six month resistance training was done on standard gym equipment. The twice-weekly sessions ran an hour in length and involved 30 contractions of each muscle group involved, similar to training sessions available at most fitness centers. The strength test was based on knee flexion.
The older participants, while generally active, had never participated in formal weight training said co-first author Tarnopolsky, who directs the Neuromuscular and Neurometabolic Clinic at McMaster University. In a four month follow up after the study was complete, he said most of the older adults were no longer doing formal exercise in a gym, but most were doing resistance exercises at home, lifting soup cans or using elastic bands. “They were still as strong, they still had the same muscle mass,” said Tarnopolsky. “This shows that it’s never too late to start exercising and that you don’t have to spend your life pumping iron in a gym to reap benefits.”
Future studies are being designed to determine if resistance training has any genetic impact on other types of human tissue, such as those that comprise organs; researchers also want to determine whether endurance training (running, cycling) impacts mitochondrial function and the aging process. The most recent study also points to particular gene expressions that could be used as starting points for chemical screenings that could lead to drug therapies that would modulate the aging process.
“The vast majority of aging studies are done in worms, fruit flies and mice; this study was done in humans,” said Melov. “It’s particularly rewarding to be able to scientifically validate something practical that people can do now to improve their health and the quality of their lives, as well as knowing that they are doing something which is actually reversing aspects of the aging process.”