**4. Evidence-based review**

Whilst there have been several treatment guidelines published, they are consensus-based rather than evidence-based [16–19]. This review seeks to address this issue and identify any gaps in research for vitamin D replacement, listing the types available including dietary, other supplementation and sunlight, for bone health (rickets, osteoporosis) as well as to address safety and efficacy in an evidence-based manner.

Systematic search of MEDLINE, CINAHL and EMBASE for articles published rom September 2015 to August 2019 and the Cochrane Database of Systematic Reviews (most recent issue searched—Issue 2, 2019) was conducted by the author. Randomised controlled trials, meta-analyses and reviews of all aspects of vitamin D supplementation in humans were reviewed. Articles pertaining to osteoporosis in a specific condition (e.g. epilepsy) were excluded.

All studies were reviewed independently by the author, who recorded individual study results, and an assessment of study quality and treatment conclusions was made according to evidence-based protocols.

**99**

*An Evidence-Based Review of Efficacy and Safety of Dietary, Natural Supplements…*

of Systematic Reviews, there were 4 suitable review articles [20–23].

which do not mandate fortification of their milk formulas.

**6. Sunlight for vitamin D replacement**

inactive sterols [24].

through supplementation.

Out of a total of 211 articles from PUBMED for vitamin D supplementation and osteoporosis, we found 22 articles satisfying the research criteria. Out of a total of 54 articles from PUBMED for vitamin D supplementation and rickets, we found 22 articles satisfying the research criteria. Of the 76 reviews from Cochrane Database

Human beings require and source vitamin D from diet, dietary supplements and

Whilst in particular for older people and those with restriction in diet, a diet rich in oily fish (which can theoretically improve 25-OHD levels and prevent vitamin D deficiency), in reality this is a challenge to achieve [24]. Only a few foods are a good source of vitamin D. These include fortified dairy products and breakfast cereals,

Apart from the flesh of fatty fish (such as salmon, tuna and mackerel) and fish liver oils, very little foods contain vitamin D. Trace amounts of vitamin D can be found in egg yolks, cheese and beef liver. These foods contain vitamin D3 and its metabolite 25(OH)D3 [25]. Vitamin D2 is contained in some mushrooms [26, 27]. In the standard Western diet, fortified foods provide most of the vitamin D [26]. For example, US milk is fortified with 100 IU/cup. (In Canada, by law its milk is fortified with 35–40 IU/100 mL and its margarine at ≥530 IU/100 g.) However, other dairy products derived from milk, such as ice-cream and cheese, are generally not fortified. Some ready-to-eat cereals for breakfast often contain small amounts of added vitamin D, as do some brands of orange juice and yogurt. Some plant-based alternatives to mild (such as drinks made from oats, almond or soy) are sometimes fortified with vitamin D to the amount (about 100 IU/cup) found in fortified cow's milk. Several countries of the developed world (e.g. United States, Canada and Australia) mandate the fortification of infant formula with vitamin D, 40–100 IU/100 kcal in the United States and 40–80 IU/100 kcal in Canada; however, this is not practical especially in those who breastfeed and those countries

Most people meet at least some of their vitamin D needs through exposure to sunlight [28]. Solar ultraviolet B radiation crosses the skin and converts 7-dehydrocholesterol to previtamin D3, which is rapidly converted to vitamin D3. Excessive sunlight exposure does not cause intoxication because any excess previtamin D3 or vitamin D3 is destroyed by sunlight, and in the skin there is reversible conversion to

In residential aged care, practical attempts for therapeutic sunlight therapy have produced only mild 25(OH)D3 improvements and depended on the season of exposure [29]. On a practical level, excessive exposure to ultraviolet is the primary cause of skin cancer, including squamous cell carcinoma, basal cell carcinoma and cutaneous malignant melanoma [30], so this is not a pragmatic approach from a public health perspective. Essentially, people with limited sun exposure require good dietary sources of vitamin D or take a supplement to achieve recommended intake levels. Besides increasing sun exposure, the best way to get additional vitamin D is

*DOI: http://dx.doi.org/10.5772/intechopen.89598*

**5. Vitamin D replacement in diet**

fatty fish, beef liver and egg yolks.

exposure to sunlight.

*An Evidence-Based Review of Efficacy and Safety of Dietary, Natural Supplements… DOI: http://dx.doi.org/10.5772/intechopen.89598*

Out of a total of 211 articles from PUBMED for vitamin D supplementation and osteoporosis, we found 22 articles satisfying the research criteria. Out of a total of 54 articles from PUBMED for vitamin D supplementation and rickets, we found 22 articles satisfying the research criteria. Of the 76 reviews from Cochrane Database of Systematic Reviews, there were 4 suitable review articles [20–23].
