Truth with a capital "T" (or capital "T" truth) is Truth that reflects Reality.
Truth with a capital "T" is universally valid and relevant for all living beings. For example, it is True that if a living body does not eat food, or drink water, it will die. It is also True that our body is merely a vessel for our Immortal Spirit (i.e. our Consciousness), that a fully functioning body (i.e. Physical Unit) is required for optimal expression and manifestation of said Consciousness, and that we attain a fully functioning body only by attending to its needs, providing it proper and supportive growing conditions, and heaping upon it lots of love and attention, especially during the sensitive phases of development during the first two decades of life.
Truth with a capital "T" can be distinguished from truth with a little "t." Truth with a little "t" is truth that is not universally valid. For example, the statement that "people like to eat meat" is a little "t" truth because it is not universally valid. Many people do like to eat meat, but more and more do not.