Mid-adulthood feels like a period of confidence and optimism. Careers are well-established, homes are nestled in for years, and children are transitioning into independence. In addition, feelings of comfort settle in as a new phase of life begins with unexpected friendships, new hobbies, or possibly grandchildren. However, this phase of life also brings on physiological, mental, and emotional challenges for women. Mid-adulthood is when many women begin to experience symptoms of perimenopause. Hot flashes, low energy levels, and brain fog become unpleasant for most women. Symptoms may continue into menopause as well as unpredictable menses, abrupt stop, or more frequent or less frequent cycles. Around the age of 50, 60% of circulating endogenous estrogen decreases along with its protective health benefits. A main long term effect of decreased estrogen is osteoporosis in women (Mahan & Raymond, 2017, 358). However, maintenance of bone health is possible by consuming a well-balanced diet, focused on key nutrients as well as implementation of daily therapeutic exercise.
Decreased circulating estrogen leads to decreased bone mass due to less bone remodeling. Bone remodeling is the process in which bone is resorbed through the action of osteoclasts and reconstructed with osteoblasts. At approximately the age of 40 osteoclastic resorption becomes greater than the formation by osteoblasts in both sexes, this is referred to as “uncoupling”. However, this occurs much greater in women after menopause and is referred to as Estrogen-androgen deficient osteoporosis (Mahan & Raymond, 2017, 459).
Adequate calcium intake is key for osteoporosis prevention as 90% of calcium is found in bone. If blood concentration of calcium is not sufficient, parathyroid hormone is released causing breakdown of bone (Gropper & Smith, 2013, 431). Current daily recommendations for bone health in women is 1,200 mg of calcium daily. Dietitians recommend that RDA levels are met firstly through foods, such as dairy, fortified nondairy milks, beverages, breads, and cereals. Leafy greens and legumes are good sources of calcium; however, absorption is lower due to absorption inhibitors such as phytic and oxalic acid. Women should ask their doctor or dietitian about supplementing calcium if they are taking corticoid steroids, have low bone mass, are perimenopausal or postmenopausal women, or are lactose intolerant or vegan (Mahan & Raymond, 2017, 463-464).
Another nutrient of focus is the sunshine Vitamin. Vitamin D directly impacts bone health because it manages calcium balance and uptake by stimulating intestinal calcium transport and osteoclast activity in bone. Decreased estrogen in menopausal women affects hydroxylase activity, this enzyme is responsible for converting Vitamin D to its active form. We depend on sunlight as our primary source of Vitamin D, therefore, 15-20 minutes of sunlight between 10 AM – 3 PM is recommended daily for the general population. In addition, foods that contain Vitamin D are egg yolk, fatty fish, some mushrooms, as well as fortified dairy and nondairy products (Mahan & Raymond, 2017, 463-464).
Although Vitamin K is not directly impacted by menopause, it still plays an important role in bone metabolism by aiding in the post translational modification of matrix proteins, such as osteocalcin. Osteocalcin makes up 10-20% of noncollagenous protein in bone. Studies show that serum levels with undercarboxylated osteocalcin are associated with low bone mineral density. Therefore, to maintain bone health, a well-balanced diet with leafy greens and vegetables, plant oils, nuts and seeds will provide adequate Vitamin K. Lastly, Magnesium, like Vitamin K is not affected by menopause, however, is needed to sustain bone density. Magnesium is involved in bone remodeling and the metabolism of parathyroid hormone and Vitamin D, which as mentioned earlier play an important role in bone homeostasis. Certain nuts, seeds, and most legumes are the best sources of Magnesium (National Institutes of Health, 2020).
In terms of the exercise management and recommendations for post-menopausal women, the research is fairly clear. Most studies have found that bone mineral density and osteogenesis are improved with a combined exercise approach (Geli et. al, 2017). Resistance exercise has shown to have the greatest osteogenic effects, so long as the load exceeds that of the individual’s activities of daily living (Physiopedia, 2020). Low to moderate impact weight bearing activities such as walking, yoga, jogging, running, swimming, and cycling, just to mention a few, have also been shown to maintain bone mineral density and promote osteogenesis (Physiopedia, 2020). The benefits of combined exercise are not restricted to bone density but have also been shown to reduce the risk of cardiovascular disease, improve body composition, and improve balance and equilibrium in post-menopausal women (Physiopedia, 2020).
In summary, resistance exercise plus weight-bearing, aerobic exercise has not only been shown safe to perform but also effective in the management of the associated long term effects of menopause. In addition, a well-balanced, nutrient dense diet will supply sufficient nourishment to maintain bone health. With proper nutrition and implementation of exercise, especially in early adulthood and throughout life, progression of osteoporosis can be delayed in postmenopausal women.
My sincere thanks to Mariana Leon for her continued support to the blog. This month she also brought collaborative approach by inviting David Orellana PT who discussed physiological maintenance and bone health.
Thank you Mariana & David for your contribution.
Mariana Leon is a first-generation university graduate. She recently graduated with her BS in Food and Nutrition from Cal Poly Pomona in 2019 and her goal is to become a Registered Dietitian Nutritionist. She strives to focus her career in preventive care, diabetes, and intuitive eating in underserved communities. She works as a nutrition assistant and serves as a student committee coordinator for IND MIG.
David Orellana is a Physical Therapist who resides with his wife and 2 year-old son in Southern California. David received a BS in Kinesiology with an emphasis in Clinical Health Sciences in 2014 at Cal Poly Pomona and later received his Doctorate of Physical Therapy from Azusa Pacific University in 2019. He is passionate about preventative healthcare, team-based healthcare, and the importance of exercise and physical medicine. These passions have made him a firm believer in the idea that exercise is medicine. With these ideas, he hopes to reach his new goals of becoming a Certified Strength and Conditioning Specialist, an Orthopedic Clinical Specialist, teaching at the undergraduate and graduate levels, and starting his own private practice. Currently, David practices at Kaiser Permanente in the orthopedic physical therapy residency.