How can mindfulness be secular, Buddhist or Christian? Richard Burnett has written an excellent, well-researched, erudite and thought-provoking thesis called 'Mindfulness in schools: learning lessons from the adults - secular and Buddhist (see link below). Within his thesis are important ideas that enable us to begin to answer the question above.
 
Firstly, mindfulness can be used in different settings because it is a universal human capacity for awareness and attention in the present-moment and must be distinguished from the meditative or mindful awareness practices that lead to this mode of awareness.  In an important note on page 6 of his thesis Burnett says, 'There is nothing 'Buddhist' about being mindful and paying attention to the present moment. Kabat-Zinn compares this to calling gravity 'British' because it was discovered by Newton.'
 
Secondly, it has a historical presence in Buddhism and Christianity, and in secular psychology there has also been a long focus on awareness and attention and the regulation of emotions. In other words people came across the capacity for mindfulness within different contexts, originally these contexts were religious.  The other key idea, then, is to understand the context.
 
Richard Burnett is someone who has looked at this question of context within the setting of introducing mindfulness into schools (http://mindfulnessinschools.org/).

Thirdly, in counselling there is an important emphasis on client autonomy, respecting a person's world view, experience and ethical values. That means boundaries are important. What is the context in which the client lives? An atheist might want to engage with a purely secular mindfulness.
 
This question of boundaries and client autonomy arises in mindfulness because it is a universal human capacity, and therefore appears in different contexts.  These forms must be well defined and clearly articulated, although there is shared territory between the forms as well as distinctives. But a secular mindfulness course must not be ‘Buddhism by the back door.’ (p.32)
 
The key question is I guess: how do we ensure secular mindfulness is secular, Buddhist mindfulness is Buddhist and Christian mindfulness is Christian, for those to whom it matters? Someone looking at life through a secular lens for example.
 
Burnett argues, quite rightly that mindfulness is schools does not have the same objective as clinical psychology, because 'in a classroom context we are not treating specific pathologies.' (p. 24). Nor can it be introduced as a spiritual practice 'as a classroom is not the place for religious instruction.' (p.24) It can be used more generally to promote the key attitudes found in the National Framework for religious education of 'self-awareness, respect for all, open-mindedness and appreciation and wonder.' (p.27)
 
It then requires what has been called an 'informational context' (Feldman); or a 'framework of understanding' (Teasdale) or what Kabat-Zinn calls 'scaffolding'. (p.28) Buddhist mindfulness is set within an ancient and complex scaffolding. (p.28) Helpfully, Burnettt argues that 'The scaffolding in clinical mindfulness may be much smaller, but is very well constructed and arguably more effective in the treatment of specific conditions.' (p.29) Mindfulness within Buddhism is set within religious or spiritual scaffolding, within clinical mindfulness it is secular (generally), although there are psychologists reframing Buddhism as a wise and ancient psychology and bringing in Buddhist insights that are psychological.
 
Burnett quotes from Kabat-Zinn, the pioneer of clinical mindfulness, as saying that mindfulness 'may have to give up being Buddhism in any formal religious sense.' (p.31) This clear boundary around clinical mindfulness to ensure it is secular is important as Burnett outlines in a quote from Michael Chaskalson, (one of the key figures in mindfulness he has interviewed): 'If you don't establish clear boundaries you will exclude some people. There will be practising Christians for example, or dedicated Dawkins style atheists coming on courses and I don't want to exclude them from conversation.' (p.31)
 
So within schools Burnett argues that mindfulness should not be Buddhist (almost certainly). (p.31) If you are doing a Religious Studies A-level in Buddhism you would refer to the Buddhist scaffolding. But when taught as a practice it should be within scaffolding that is clearly secular. In that context what it can address, as a backbone for the engagement, is what Mark Williams calls 'universal vulnerabilities.'   Although specific vulnerabilities identified in the context of schools such as 'anxiety of exams,’ peer pressure, or mood swings,  could be indicated to pupils. (p.33)
Burnett argues that mindfulness, especially in schools, brings with it ‘a sense of possibility.’ ( p.33). Burnett  highlights these other possibilities, pointing out that there are a broad 'range of potential applications', including functional, therapeutic, to more spiritual applications when the context is appropriate. (p.33)
 
What I have been trying to develop, through 'A Book of Sparks: a Study in Christian MindFullness' and other writings,  is a Christian scaffolding, drawing on biblical and historical roots for the development of mindfulness within the Christian tradition, as well as looking at the benefits of engaging with it today.
 
Within this setting I believe it has spiritual as well as therapeutic benefits, because of the overlaps, and shared territory, and because we are 'embodied' people. The evidence-based research within clinical psychology suggests that it would also be appropriate to point Christians, under the holistic guidance of doctors and therapists, to secular clinical mindfulness which might address 'specific' vulnerabilities they might be living with. For Christians are not immune from the universal and specific vulnerabilities that afflict all human beings.
 
Within this research I am keen to work collaboratively with other Christians who are interested in mindfulness, both psychologically and theologically. I am grateful for the collaborative partnerships that are beginning. Space doesn’t permit a description of the scaffolding that makes mindfulness Christian, I have done that elsewhere, but I do believe that for Christians, as well, as they rediscover their contemplative roots, it has a very real ‘sense of possibility.’

http://mindfulnessinschools.org/images/files/keyDocuments/Mindfulness_inSchools_Burnett.pdf