October 16, 2018
by Wendy E. Ward, BArts&Sci, BSc, MSc, PhD; Peter C. Fritz, BSc, DDS, FRCD(C), PhD, MBA
Diet and Peridontal Health
Many epidemiological studies have shown positive associations between specific nutrients – including calcium, vitamins C and D, specific fatty acids – and periodontal health. 1,2 Protein is a much less studied nutrient from this perspective although it serves as a building block for bone and the periodontium, and also assists with repair of these tissues. Protein has been studied in terms of bone health and risk of fracture, with many but not all studies reporting that higher intakes of protein are associated with higher bone mineral density (BMD). 3 The association between bone and periodontal health, specifically lower hip and/or spine BMD being associated with greater tooth loss and/or clinical attachment loss, 4,5 may suggest that the periodontium is also influenced by dietary protein intake. Protein is often a nutrition topic of interest given general societal interest in plant-based diets for health, and issues relating to sustainability of the food supply. This nutrition update will provide an overview of the link between periodontal and bone health, and also discuss the potential role of higher than recommended levels of protein intake for musculoskeletal health including periodontal health. Practical aspects about how to incorporate current recommended levels of protein in the diet, with consideration of energy levels and other bone-supporting nutrients in foods, will also be discussed.
Association Between Periodontal Disease and Osteoporosis
Before discussing protein in relation to periodontal health, it is helpful to first discuss the association between periodontal disease and osteoporosis. Beyond the inflammation and destruction of the periodontal ligament, periodontal disease involves a loss of alveolar bone that resembles the loss of bone mineral and structure that occurs with osteoporosis. Low BMD measured at the hip and/or spine are typically the skeletal sites from which a diagnosis of osteoporosis is made. Both conditions have some similar risk factors: smoking, diabetes and aging. Also, changes in bone remodelling leading to bone loss is a shared characteristic, and is, at least in part, influenced by hormonal status (i.e. decline in endogenous estrogen production) and inflammation. It is not known for certain whether osteoporosis (currently measured as low BMD at hip or spine) predisposes individuals to periodontal disease. Some but not all studies show a greater loss of alveolar bone in individuals with low bone BMD. 4 A recent systematic review summarized the findings from 15 studies, representing several different countries throughout the world, that studied the association between periodontal disease and osteoporosis in postmenopausal women. 4 Interestingly, 10 out of the 15 studies showed a significant association between clinical attachment loss (CAL) and osteoporosis (defined by low BMD at hip and/or spine). While periodontal disease is a complex dynamic interplay of multiple causal factors and osteoporosis may have an inflammatory aspect, the involvement of lifestyle, systemic factors and bone loss link the two conditions. Thus, perhaps what we know about protein influencing musculoskeletal health also applies to periodontium.
How Much Protein?
The current recommendation for protein intake is 0.8 g of protein per kg body weight, and unlike for many other nutrients such as calcium and vitamin D that have higher requirements with aging, this recommendation does not increase with age during adulthood. 6 However, as will be discussed later in this update, there is a substantive literature showing that higher intakes of protein may help to preserve muscle mass and strength during aging, and is also associated with healthier bone, and potentially a reduced risk of fracture.
Table 1 shows the level of protein in a variety of foods that are commonly consumed by Canadians, and from this you can estimate the servings of protein required to meet the recommended intake for protein (Table 1). For example, an individual who is an average body weight of 60 kg should consume, approximately, 48 g of protein per day. Using the list of foods in Table 1, animal sources of protein (chicken, steak, beef, salmon) contain higher amounts of protein compared to plant sources of protein (quinoa, beans, nuts, flaxseed) per serving. Another observation can be that the amount of energy can differ widely among different food sources of protein. In other words, animal sources of protein have a higher amount of protein per unit of energy than many of the plant-based sources. This may be an important consideration if trying to increase intake of protein but minimize an increase in energy intake. Moreover, with aging, a decline in appetite and/or food preferences can be altered; both of these aspects may dictate what foods an individual chooses to consume. Other considerations when choosing a protein source, particularly in terms of bone health which also includes alveolar bone, may be the calcium and vitamin D content and/or fat profile of a food. Calcium will be most abundant in milk and yogurt, vitamin D in salmon, and salmon along with nuts, beans and flaxseed, contain the healthful omega-3 and omega-6 fatty acids.
Do higher protein intakes benefit health? A number of expert groups have published recommendations for higher intakes of protein to attenuate the decline in muscle mass and function, termed ‘sarcopenia’, that occurs with aging. 7-9 Intakes of 1 to 1.2 g protein per kg body weight is generally the level being suggested for the healthy older adult. Reasons for the purported higher need during aging is an overall compromised ability of the body to respond to protein. This can be due to a lower ability to digest protein and absorb and utilize resulting amino acids. Muscle, in particular, has been shown to have an attenuated response to dietary protein in comparison to young healthy individuals. Prospective studies have shown there is less loss of muscle mass and function among older adults consuming higher intakes of protein. 7-9 While the response of bone has not been studied as extensively as for muscle, several cohort studies identify a positive association between higher protein intakes (that in some studies is similar to a consumption of 1 to 1.2 g protein per kg body weight per day) and higher bone mineral density. 3 Although, longer-term and well-controlled studies are needed to determine whether higher protein is an effective preventive or treatment strategy against osteoporosis. One study identified that dietary calcium modulates the association between protein and risk of hip fracture. 10 Individuals consuming calcium at a level below the current recommended intake showed an association with higher risk of hip fracture whereas the reverse was shown among those consuming higher levels of calcium. There was an association with a reduced risk of hip fracture. Thus, it is important that the recommended level of calcium is consumed. Given the important role for vitamin D in aiding absorption of calcium in the intestine, it is also critical that individuals consume recommended levels of vitamin D.
Do higher protein intakes benefit periodontal health? Whether or not higher protein intakes are specifically associated with better periodontal health is not known. However, given the aforementioned link between loss of teeth and loss of BMD at other skeletal sites (hip, spine), it is possible that alveolar bone supporting teeth may have a similar response to higher protein as other skeletal sites. There is a study that suggests that higher protein intakes are associated with better healing after sanative therapy. 11 In this study, protein intakes were measured using a food frequency questionnaire. Patient data was grouped by level of protein intake into two groups: <1 g protein per kg body weight per day or > 1 g protein per kg body weight per day. Between the two levels of protein intake, baseline clinical characteristics (number of teeth, number of sites with probing depth > 4 mm, number of sites with bleeding on probing, plaque index), presence of comorbidities and number of medications used were similar between the two groups. Patients were also non-smokers. The cut-point of 1 g protein per kg body weight per day was used to reflect the most recent data and advice of expert panels that protein intake should be higher for older adults. Mean patient age was 57 and 61 years for the lower and higher protein intake groups, respectively. The main finding from the study is that the higher protein intake was associated with fewer probing depth sites > 4 mm. While this finding suggests that optimizing protein intake supports healing after sanative therapy, further study is required to determine cause and effect as well as potential mechanisms of action.
Guidance for Patients
When making choices about protein sources, think about the whole food and what it offers, not only in terms of protein but other nutrients. Of particular relevance for maintenance of bone health is calcium and vitamin D. The fat profile and energy intake may also be aspects to consider.
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About the Author
Wendy Ward is a Professor and Canada Research Chair in the Department of Kinesiology in the Faculty of Applied Health Sciences at Brock University. Her research program investigates how early diet sets a trajectory for a stronger, healthier skeleton at adulthood, and also how diet can support bone health at older life stages. Within this research program, a number of novel foods and food components are studied: vitamin D, soy and its isoflavones, omega-3 fatty acids in flaxseed and fish oil, and tea and its flavonoids.
Peter Fritz is a certified specialist in Periodontics in Fonthill, Ontario. His translational research program investigates optimal collaborative strategies for periodontal wellness throughout the lifecycle involving nutrition, advanced instrumentation, microsurgery and tissue regeneration.