After You Eat an Apple: This Is What REALLY Happens to Your Cholesterol — Transcript

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1. 0:00You bite into an apple. Within minutes,
2. 0:02its sugars are being released. Its
3. 0:05nutrients are moving through your
4. 0:06digestive system.
5. 0:08But something else in that apple is
6. 0:09taking a very different journey.
7. 0:12Pectin.
8. 0:13Pectin is a type of soluble fiber. Fiber
9. 0:16that interacts with water and can make
10. 0:18the contents of your intestine more
11. 0:20viscous, almost gel-like. And unlike the
12. 0:23apple's sugars, pectin isn't simply
13. 0:25absorbed into your bloodstream.
14. 0:28Instead, it continues through your
15. 0:30digestive tract. And what happens there
16. 0:32may eventually influence something
17. 0:34seemingly far away. The cholesterol
18. 0:36circulating in your blood. But there's
19. 0:38an important distinction.
20. 0:41Eating one apple doesn't suddenly vacuum
21. 0:43cholesterol out of your arteries. So
22. 0:45what actually happens? Let's follow the
23. 0:47apple. The apple enters your digestive
24. 0:50system. The first major changes begin
25. 0:52when you chew.
26. 0:54Your teeth crush the apple structure,
27. 0:56breaking open plant cells and exposing
28. 0:58carbohydrates, fiber, vitamins, and
29. 1:01thousands of plant compounds to
30. 1:03digestion.
31. 1:04Once swallowed, the apple reaches your
32. 1:06stomach. Then the partially digested
33. 1:09food enters your small intestine.
34. 1:11This is where the story splits. Some of
35. 1:14the apple's carbohydrates are broken
36. 1:16down into simple sugars and absorbed
37. 1:18through the intestinal wall. They can
38. 1:20enter your circulation and be used by
39. 1:22your cells for energy.
40. 1:24But much of the fiber can't be digested
41. 1:26by your own digestive enzymes.
42. 1:29And one particular type matters for
43. 1:31today's story. Pectin.
44. 1:33Pectin is concentrated in the cell walls
45. 1:35of fruits such as apples. And because
46. 1:37it's a soluble fiber, it can interact
47. 1:40with the watery environment inside your
48. 1:42intestine.
49. 1:43That changes what happens next. Your
50. 1:45liver sends something into the
51. 1:47intestine. To understand what an apple
52. 1:49has to do with cholesterol, we need to
53. 1:51talk about something you probably don't
54. 1:53think about while eating. Bile.
55. 1:56Your liver makes bile acids from
56. 1:58cholesterol.
57. 1:59They're stored and concentrated in your
58. 2:01gallbladder. And when food enters your
59. 2:03small intestine, bile helps your body
60. 2:05digest and absorb fats.
61. 2:07But your body is economical.
62. 2:09It doesn't normally throw all those bile
63. 2:11acids away.
64. 2:13Most are eventually reabsorbed from the
65. 2:14intestine and returned to the liver.
66. 2:17Think of it as a recycling system.
67. 2:19Liver, bile, intestine, back to liver.
68. 2:24And this is where soluble fiber becomes
69. 2:26interesting. Research suggests that
70. 2:28viscous soluble fibers can interfere
71. 2:30with the normal intestinal handling and
72. 2:32reabsorption of bile acids, increasing
73. 2:35the amount that ultimately leaves the
74. 2:37body rather than being recycled.
75. 2:40The precise molecular interactions are
76. 2:42more complicated than saying the fiber
77. 2:44simply grabs bile. And viscosity appears
78. 2:47to be an important part of the
79. 2:48mechanism. Why does that matter? Because
80. 2:51bile acids don't appear from nowhere.
81. 2:54Remember what your liver used to make
82. 2:55them?
83. 2:56Cholesterol.
84. 2:58The after you eat moment. This is the
85. 3:00key moment. The apple itself never
86. 3:02travels to your liver and cleans
87. 3:04cholesterol from your blood. Instead,
88. 3:07its soluble fiber stays largely inside
89. 3:09the digestive tract.
90. 3:11There, it can alter the environment in
91. 3:13which bile acids are normally recycled.
92. 3:16If more bile acids are lost through the
93. 3:18digestive tract, the liver has to
94. 3:20maintain its bile acid supply. And
95. 3:23cholesterol is one of the raw materials
96. 3:25it uses.
97. 3:27One way the liver can obtain cholesterol
98. 3:29is by taking up more LDL particles from
99. 3:32the bloodstream.
100. 3:33LDL stands for low-density lipoprotein.
101. 3:36People often call it bad cholesterol.
102. 3:39But technically, LDL isn't cholesterol
103. 3:42itself.
104. 3:43It's a particle that carries cholesterol
105. 3:45through your blood.
106. 3:46So the pathway looks something like
107. 3:48this.
108. 3:49Apple,
109. 3:50pectin, soluble fiber, intestinal
110. 3:53environment changes, bile acid recycling
111. 3:56can be reduced, liver cholesterol
112. 3:58handling changes, more LDL can be
113. 4:00cleared from the blood, LDL cholesterol
114. 4:03may fall over time. That's the
115. 4:05connection between an apple in your hand
116. 4:08and a cholesterol number on your blood
117. 4:09test. But that's still a mechanism. The
118. 4:12more important question is, does eating
119. 4:15actual apples change cholesterol in
120. 4:17actual people? What happened when
121. 4:19researchers tested whole apples? One
122. 4:22particularly useful randomized
123. 4:24controlled trial studied 40 adults with
124. 4:27mildly elevated cholesterol. Their
125. 4:29average age was about 51. For 8 weeks,
126. 4:32participants ate two whole apples every
127. 4:35day. During another 8-week period, they
128. 4:38consumed a drink matched for sugar and
129. 4:40calories instead. That comparison
130. 4:42matters because if both contain similar
131. 4:45amounts of sugar and energy, but the
132. 4:47whole apple produces a different result,
133. 4:49researchers can start investigating what
134. 4:51the intact fruit matrix, including its
135. 4:54fiber and polyphenols, might be doing.
136. 4:57After the whole apple period, the
137. 4:59researchers found lower total
138. 5:00cholesterol and lower LDL cholesterol
139. 5:03compared with the control drink. They
140. 5:05also observed changes in some other
141. 5:07cardiovascular markers.
142. 5:09Notice what this study does not prove.
143. 5:12It doesn't prove that one apple lowers
144. 5:13your cholesterol immediately after you
145. 5:15eat it. It doesn't prove that apples can
146. 5:17replace cholesterol medication. And it
147. 5:21doesn't mean everybody will experience
148. 5:22the same change.
149. 5:24The study tested two apples per day for
150. 5:268 weeks in people with mildly elevated
151. 5:29cholesterol. That's very different from
152. 5:31saying, "Eat this apple tonight and your
153. 5:34LDL will be lower tomorrow morning." The
154. 5:36effect we're talking about is a dietary
155. 5:39pattern operating repeatedly over time.
156. 5:42There's another journey happening. Not
157. 5:44all of the apple's fiber finishes its
158. 5:46story in the small intestine.
159. 5:48Some reaches your colon.
160. 5:50And there it encounters something
161. 5:51completely different. Your gut
162. 5:53microbiome.
163. 5:55Those are the enormous communities of
164. 5:57microorganisms living inside your
165. 5:59digestive tract. Some of them can
166. 6:01ferment components of fiber that your
167. 6:03own digestive enzymes couldn't break
168. 6:05down.
169. 6:06That fermentation produces compounds
170. 6:08called short-chain fatty acids.
171. 6:11In plain English, these are small
172. 6:13molecules produced when certain gut
173. 6:15microbes feed on fermentable
174. 6:16carbohydrates.
175. 6:18Researchers have proposed that some of
176. 6:19these compounds may influence
177. 6:21cholesterol metabolism in the liver.
178. 6:23Apple polyphenols, plant compounds found
179. 6:26in apples, may also contribute.
180. 6:28But here's where we need to be careful.
181. 6:31These mechanisms are biologically
182. 6:33plausible and supported to different
183. 6:34degrees by laboratory, animal, and human
184. 6:38evidence.
185. 6:39But the cholesterol effect of whole
186. 6:40apples shouldn't be attributed to one
187. 6:43single pathway with certainty.
188. 6:45The combined effects of fiber,
189. 6:47polyphenols, bile acid metabolism, and
190. 6:50the gut microbiome may all contribute.
191. 6:53In other words, the apple is a whole
192. 6:55biological package.
193. 6:57What about apple juice?
194. 6:59And this reveals something important.
195. 7:01An apple and apple juice are not
196. 7:03physiologically identical just because
197. 7:05they came from the same fruit.
198. 7:07When you eat a whole apple, you're
199. 7:09consuming its intact food structure and
200. 7:11fiber.
201. 7:12Juicing can remove much of that fiber.
202. 7:15That's particularly relevant here
203. 7:16because the fiber is part of the
204. 7:18mechanism we're investigating.
205. 7:20In the randomized trial we just
206. 7:22discussed, whole apples were compared
207. 7:24with a sugar and energy-matched apple
208. 7:26beverage.
209. 7:27The whole apples lowered LDL cholesterol
210. 7:30relative to that beverage.
211. 7:32So when we're talking about this
212. 7:33potential cholesterol effect, the whole
213. 7:35fruit matters. So should you start
214. 7:38eating an apple every day?
215. 7:40An apple can certainly be part of a
216. 7:42heart-healthy dietary pattern,
217. 7:44but don't turn it into medicine.
218. 7:46Your LDL level is influenced by many
219. 7:49things. Your overall diet, genetics,
220. 7:52body weight, physical activity, age,
221. 7:55certain medical conditions, and
222. 7:57medications.
223. 7:58An apple doesn't erase the effects of
224. 8:00everything else you eat.
225. 8:02And if you've been prescribed
226. 8:03cholesterol-lowering medication, this
227. 8:05isn't a reason to stop taking it.
228. 8:08What the evidence gives us is something
229. 8:10subtler and scientifically much more
230. 8:13interesting.
231. 8:14A simple whole food can interact with
232. 8:16your digestive system in ways that, when
233. 8:18repeated regularly, may contribute to
234. 8:21measurable changes in cholesterol
235. 8:22metabolism.
236. 8:24An apple doesn't enter your bloodstream
237. 8:26and scrub cholesterol away.
238. 8:28Part of its fiber stays in your
239. 8:30intestine,
240. 8:31changes what happens to bile,
241. 8:33which can change what your liver does
242. 8:35with cholesterol.
243. 8:37And when that happens repeatedly over
244. 8:38time, your LDL cholesterol may come down
245. 8:41modestly.
246. 8:43That's what can happen after you eat.
247. 8:46Subscribe to After You Eat and discover
248. 8:48what your food does next.