Eating nutrient-rich prunes every day may reduce inflammatory factors that contribute to osteoporosis

A study in postmenopausal people suggests eating nutrient-rich prunes every day may be beneficial to bone health, reducing inflammatory factors that contribute to osteoporosis.

The research will be presented this week in Philadelphia at the American Physiological Society’s (APS) annual meeting at Experimental Biology 2022.

An estimated 13.6 million people in the U.S. over the age of 50 will develop osteoporosis – a loss of bone strength caused by reduced mineral density of the bones – by the year 2030. Osteoporosis increases the risk of fracture, especially in older adults. People who experience menopause have lower levels of estrogen, which trigger an increase in inflammation in the body, which can also contribute to bone loss.

Previous research has shown that polyphenol extracts – plant compounds that act as antioxidants and reduce inflammation—in prunes promote lower levels of oxidative stress and inflammation in a type of bone cell called osteoclasts.

In a new study, researchers from the Integrative and Biomedical Physiology Program and the Departments of Nutritional Sciences and Kinesiology at The Pennsylvania State University explored the effects of prunes on bone health after menopause.

Postmenopausal women with a bone mineral density score that was defined as low – a marker of osteoporosis – were divided into three groups:

One group ate 50 grams (g) of prunes (about six prunes) daily for 12 months.
A second group ate 100 g of prunes (about 12 prunes) daily for 12 months.
A control group ate no prunes.

More information: Abstract: “A randomized controlled trial of dietary supplementation with prunes (dried plums) on inflammatory markers in postmenopausal women” experimentalbiology.org/

The 2015–2020 Dietary Guidelines for Americans (DGA) advocate for healthy eating patterns that include a variety of fruits. This includes all fresh, frozen, canned and dried fruits and fruit juices [1]. The recommended intake of fruit in the Healthy US-Style Eating Pattern at the 2000-kcal level is two cup-equivalents of fruit per day.

Increasing the amount and variety of fruits Americans consume is a strategy that helps individuals meet a wide range of nutrient requirements. However, per the 2015–2020 DGA, average intake of fruit is well below recommendations for almost all age-sex groups, except in children ages 1–8 years [1]. Average intake of fruit is lowest among girls ages 14–18 years and in women age 51+ years [1], two critical time points in bone development and maintenance.

Osteoporosis is a rising public health concern, given the aging population and suboptimal dietary intakes of dairy, fruits, vegetables and whole grains, which provide a variety of essential nutrients that influence bone accretion and maintenance across the lifespan. The National Osteoporosis Foundation estimates that 10.3% of Americans over the age of 50 years have osteoporosis (t-score ≤ 2.5), and 43.9% have low bone mass (also commonly referred to as osteopenia; t-score ≤ 1.0), a risk factor for osteoporosis [2].

The risk of fractures increases with age among individuals age 50+, and differs by sex, race and ethnicity [2,3]. Although many factors contribute to this debilitating event, the most significant causes are reduction in bone mass, structural deterioration and increased frequency of falls.

It 2005, it was estimated that the over two million incident osteoporotic fractures occurring annually in the U.S. had an economic burden of $16.9 billion, which is anticipated grow to three million fractures at a cost of $25.3 billion by 2025 [4]. Men account for 29% of these fractures and 25% of the cost burden [4]. Optimization of lifestyle factors known to influence bone mass and strength is an important strategy aimed at reducing the risk of fractures later in life.

Plums are a type of drupe fruit that belong to the subgenus Prunus (family Rosaceae). They differ from other subgenera of drupe fruits (cherries, peaches, etc.) since the shoots have a terminal bud and unclustered single side buds, flowers combine in groups of one to five on short stems, the fruit has a crease running down one side and a smooth seed.

There are over 40 species of plums currently documented, although two species, the European plum (Prunus domestica) and Japanese plum (Prunus salicina and hybrids) are of commercial significance globally [5]. The origin of European plum is thought to have been near the Caspian Sea, while Japanese plums originated in China, but derived their name from the country where they were cultivated.

European plums were introduced in the U.S. by pilgrims in the 17th century, while Japanese plums were introduced to the U.S. in the late 19th century. China, Serbia and Romania are the world’s leading producers of plums. Worldwide, greater than 11.2 million metric tons of plums were harvested in 2014 per the Food and Agriculture Organization (FAO) of the United Nations [6].

While all prunes originate from fresh plums, not all plum varieties are considered prunes. Commercialized prunes, also commonly known as dried plums, are the dehydrated version of the cultivar Prunus domestica L. cv d’Agen. This specific variety has a naturally-occurring sugar content that enables it to be dried while still containing the pit, without being fermented. The State of California produces ~99% of the plums in the U.S. and ~40% of the world’s dried plums [7].

Dried plums are widely known for their laxative effect, which is commonly attributed to their dietary fiber content [8], but is also likely influenced by the significant amounts of phenolics (e.g., chlorogenic acid) and sorbitol present in the fruit. Dried plums are not only a source of dietary fiber, but also a good source of potassium and vitamin K (Table 1).

One serving or ~4 dried plums is 92 kilocalories and provides 2.4 g of dietary fiber, 280 mg of potassium and 22.8 µg of vitamin K. Dried plums also contain several dietary bioactives, including phenolic compounds, such as 3-caffeoylquinic acid, 4-caffeoylquinic acid, 5-caffeoylquinic acid, 3-p-coumarolylquinic acid, caffeic acid, p-coumaric acid and quercetin-3-O-rutinoside [9], whose benefits may extend beyond the basic nutrition requirements of humans.

There is an emerging body of evidence from laboratory, animal and human studies that suggests that dried plums may exert an effect on bone health. Hooshmand and others found that two servings (100 g) of dried plums per day slowed the rate of bone turnover and helped to improve bone mineral density (BMD) in a clinical study of 160 randomized postmenopausal women (100 completed the study) not receiving hormone replacement therapy [10]. A more recent clinical study by the same group confirmed the bone protective effects in postmenopausal women receiving one serving of dried plums per day [11]. However, a comprehensive review of dried plums and bone health is not currently present in the peer-reviewed scientific literature.

Table 1

Nutritional profile of dried plums per 100 g.

reference link :https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5409740/